Broadcasting signal transmitter/receiver and broadcasting signal transmission/reception method

ABSTRACT

A broadcasting signal reception method according to the present invention comprises the following steps: OFDM-demodulating by receiving a plurality of broadcasting signals, which contain a transmission frame for transmitting a broadcasting service; outputting the transmission frame by decoding a plurality of OFDM-demodulated broadcasting signals with at least one method among MIMO, MISO, and SISO; and selectively decoding a plurality of PLP&#39;s, which are included in the transmission frame, using signaling information included in the transmission frame. In particular, PSI/SI such as PAT/PMT can be transmitted through an arbitrary PLP among the plurality of PLP&#39;s; and in the transmitter, an arbitrary PLP, which transmits the PAT/PMP, can be decoded first to enable a search of all PLP&#39;s that transmit components included in a single broadcasting service, and a plurality of PLP&#39;s can be decoded selectively.

FIELD OF THE INVENTION

The present invention relates to a broadcast signal transmitter/receiverand a broadcast signal transmitting/receiving method, and, mostparticularly, to a broadcast signal transmitter/receiver and a broadcastsignal transmitting/receiving method to increase a data transmissionefficiency, to transmit a broadcast signal that can maintain acompatibility with a conventional broadcast signal transmitter/receiver,and to transmit signaling information that can receive a broadcastsignal according to the characteristics of the receiver.

BACKGROUND ART

As the time has neared to end (or terminate) the transmission of analogbroadcast signals, diverse technologies for transceiving (i.e.,transmitting and receiving) digital broadcast signals are beingresearched and developed. Herein, a digital broadcast signal may includehigh capacity video/audio data as compared to an analog broadcastsignal, and, in addition to the video/audio data, the digital broadcastsignal may also include diverse additional data.

More specifically, a digital broadcasting system for digitalbroadcasting may provide HD (High Definition) level images,multiple-channel sound (or audio), and a wide range of additionalservices. However, a data transmission efficiency for transmitting highcapacity data, a robustness of a transceiving (transmitting andreceiving) network, and flexibility in a network considering mobilereceiving equipments are still required to be enhanced.

DETAILED DESCRIPTION OF THE INVENTION Technical Objects

A object of the present invention is to provide a method and apparatusfor transceiving broadcast signals, which can receive digital broadcastsignals without error even under an indoor environment or using mobilereceiving equipment. Another object of the present invention is toprovide a broadcast signal transceiver for transceiving broadcastsignals and a method for transceiving a broadcast signals, which cantransmit signaling information to receive broadcast signals according tothe characteristics of the receiver.

Yet another object of the present invention is to provide a broadcastsignal transceiver for transceiving broadcast signals and a method fortransceiving a broadcast signals, which can maintain compatibility witha conventional broadcast system.

Technical Solutions

In order to achieve the above-described technical objects of the presentinvention, according to an aspect of the present invention, a broadcastsignal receiver may include an OFDM demodulator configured to receive aplurality of broadcast signals, each including a transmission frame fortransmitting a broadcast service, and to perform OFDM demodulation onthe received broadcast signals, wherein the transmission frame includesa preamble and multiple PLPs including a base layer and an enhancementlayer of the broadcast service, and wherein the preamble includes firstsignaling information, and wherein the multiple PLPs include secondsignaling information and third signaling information, a processorconfigured to decode each of the OFDM-demodulated multiple broadcastsignals by using at least one of MIMO, MISO, and SISO methods, and tooutput the transmission frame, a first decoder 110200 configured todecode first signaling information included in a preamble of theoutputted transmission frame, wherein the first signaling informationincludes a first identifier configured to identify each of the multiplePLPs, and a second decoder 110100 configured to decode the secondsignaling information, to decode a PLP including the third signalinginformation by using the decoded second signaling information, and toselectively decode the multiple PLPs by using the third signalinginformation, wherein the second signaling information includes adescriptor including a second identifier configured to indicate a PLPincluding the third signaling information, and wherein the thirdsignaling information including a third identifier configured toidentify a type of data, among the base layer and the enhancement layerof a broadcast service, being included in each of the multiple PLPs.

Effects of the Invention

According to the present invention, in a digital broadcasting system, byusing a MIMO system, the data transmission efficiency may be increased,and the Robustness of the broadcast signal transception (transmissionand/or reception) may be enhanced.

Additionally, according to the present invention, due to the MIMOprocessing, the receiver may efficiently recover the MIMO receptionsignals even in diverse broadcasting environments.

Moreover, according to the embodiment of the present invention, byperforming a maximum usage of the related art transceiving (transmittingand/or receiving) system while using the MIMO system, the presentinvention may provide an apparatus for transmitting/receiving abroadcast signal and a method for transmitting/receiving a broadcastsignal that can ensure backward compatibility. And, the presentinvention may provide an apparatus for transmitting/receiving abroadcast signal and a method for transmitting/receiving a broadcastsignal that can selectively (or optionally) receive or process datadepending upon the characteristics of the receiver.

Furthermore, according to the present invention, the present inventionmay provide an apparatus for transmitting/receiving a broadcast signaland a method for transmitting/receiving a broadcast signal that canreceive digital broadcast signals through a mobile receiving device orin an in-door environment without any error.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a broadcast signal transmitter using a MIMO schemeaccording to an embodiment of the present invention.

FIG. 2 illustrates an input processing module 101200 according to anembodiment of the present invention.

FIG. 3 illustrates a stream adaptation block 102200 included in an inputprocessing module according to another embodiment of the presentinvention.

FIG. 4 illustrates a BICM encoder 101300 according to an embodiment ofthe present invention.

FIG. 5 illustrates a frame builder 101400 according to an embodiment ofthe present invention.

FIG. 6 illustrates an OFDM generator 101500 according to an embodimentof the present invention.

FIG. 7 illustrates a broadcast signal receiver according to anembodiment of the present invention;

FIG. 8 illustrates an OFDM demodulator 101800 according to an embodimentof the present invention.

FIG. 9 illustrates a frame demapper 107200 according to an embodiment ofthe present invention.

FIG. 10 illustrates a BICM decoder 107300 according to an embodiment ofthe present invention.

FIG. 11 illustrates an output processing module 107500 of the broadcastsignal receiver according to an embodiment of the present invention.

FIG. 12 illustrates a structure of a PLP based additional transmissionframe according to an embodiment of the present invention.

FIG. 13 illustrates structures of an FEF based additional transmissionframe according to an embodiment of the present invention.

FIG. 14(A) and FIG. 14(B) illustrate a procedure of generating a P1symbol for identifying a additional transmission frame according to anembodiment of the present invention.

FIG. 15 illustrates L1-pre signaling information according to anembodiment of the present invention.

FIG. 16 illustrates L1-post signaling information according to anembodiment of the present invention.

FIG. 17 illustrates L1-post signaling information according to anotherembodiment of the present invention.

FIG. 18 illustrates an MIMO broadcast signal transceiver using SVCaccording to a first embodiment of the present invention.

FIG. 19 illustrates a MIMO broadcast signal transceiver using SVCaccording to a second embodiment of the present invention.

FIG. 20 illustrates a MIMO broadcast signal transceiver using SVCaccording to a third embodiment of the present invention.

FIG. 21 illustrates a structure of a transmission stream transmitted bya terrestrial broadcast system to which a MIMO transmission system usingSVC according to an embodiment of the present invention is applied.

FIG. 22 illustrates a MIMO broadcast signal transceiving systemaccording to an embodiment of the present invention.

FIG. 23 illustrates a method of transceiving data dependent on MIMOtransmission of an SM scheme in channel environment according to anembodiment of the present invention.

FIG. 24 illustrates an MIMO transmitter and an MIMO receiver accordingto an embodiment of the present invention.

FIG. 25 illustrates an MIMO transmitter and an MIMO receiver accordingto another embodiment of the present invention.

FIG. 26 illustrates an MIMO transmitter and an MIMO receiver accordingto another embodiment of the present invention.

FIG. 27 illustrates an MIMO transmitter and an MIMO receiver accordingto another embodiment of the present invention.

FIG. 28 illustrates a structure of a super frame for transmitting anadditional broadcast signal according to an embodiment of the presentinvention.

FIG. 29 illustrates an OFDM generator of the transmitter for insertingan AP1 symbol according to an embodiment of the present invention.

FIG. 30 illustrates a structure of a P1 symbol and a structure of an AP1symbol according to an embodiment of the present invention.

FIG. 31 illustrates an OFDM demodulator according to another embodimentof the present invention.

FIG. 32 illustrates a broadcast system according to another embodimentof the present invention.

FIG. 33 illustrates a block diagram showing a process of receiving a PLPbest-fitting the purpose of a receiver respective to the broadcastingsystem according to an embodiment of the present invention.

FIG. 34 illustrates a transmission frame according to an embodiment ofthe present invention.

FIG. 35 illustrates fields included in L1 signaling information regionof FIG. 34 according to an embodiment of the present invention.

FIG. 36 illustrates fields included in L1 signaling information regionof FIG. 34 according to another embodiment of the present invention.

FIG. 37 illustrates a conceptual diagram of a correlation between aservice and a PLP group according to a first embodiment of the presentinvention.

FIG. 38 illustrates an exemplary delivery system descriptor fieldaccording to the first embodiment of the present invention.

FIG. 39 illustrates a flow chart showing the process steps of a servicescanning method of the receiver according to the first embodiment of thepresent invention.

FIG. 40 illustrates a conceptual diagram of a correlation between aservice and a PLP group according to a second embodiment of the presentinvention.

FIG. 41 illustrates an exemplary component ID descriptor field accordingto the second embodiment of the present invention.

FIG. 42 illustrates a flow chart showing the process steps of a servicescanning method of the receiver according to the second embodiment ofthe present invention.

FIG. 43 illustrates a conceptual diagram of a correlation between aservice and a PLP according to a third second embodiment of the presentinvention.

FIG. 44 illustrates an exemplary delivery system descriptor fieldaccording to the third embodiment of the present invention.

FIG. 45 illustrates an exemplary component ID descriptor field accordingto the third embodiment of the present invention.

FIG. 46 illustrates an exemplary PLP_PROFILE field according to thethird embodiment of the present invention.

FIG. 47 illustrates a flow chart showing the process steps of a servicescanning method of the receiver according to the third embodiment of thepresent invention.

FIG. 48 illustrates a conceptual diagram of a correlation between aservice and a PLP according to a fourth second embodiment of the presentinvention.

FIG. 49 illustrates an exemplary IP/MAC_loc information field accordingto the fourth embodiment of the present invention.

FIG. 50 illustrates a flow chart showing the process steps of a servicescanning method of the receiver according to the fourth embodiment ofthe present invention.

FIG. 51 illustrates a flow chart showing a method of receiving abroadcast signal according to the fourth embodiment of the presentinvention.

BEST MODE FOR CARRYING OUT THE PRESENT INVENTION

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts. And, thescope and spirit of the present invention will not be limited only tothe exemplary embodiments presented herein. Although the terms used inthe present invention are selected from generally known and used terms,the detailed meanings of which are described in relevant parts of thedescription herein. It should be noted that the terms used herein mayvary depending upon the intentions or general practice of anyone skilledin the art and also depending upon the advent of a novel technology.Some of the terms mentioned in the description of the present inventionhave been selected by the applicant at his or her discretion, terms usedherein. Furthermore, it is required that the present invention isunderstood, not simply by the actual terms used but by the meaning ofeach term lying within.

Various technologies are being adopted in the digital broadcastingsystem in order to enhance the transmission efficiency and to performrobust communication. Herein, a method of using multiple antennae in thetransmitting end or in the receiving end is being proposed as an exampleof such various technologies. And, such method may be further dividedinto a single antenna transmission single antenna reception method(SISO; Single-Input Single-Output), a single antenna transmissionmultiple antennae reception method (SIMO; Single-Input Multi-Output), amultiple antennae transmission single antenna reception method (MISO;Multi-Input Single-Output), and a multiple antennae transmissionmultiple antennae reception method (MIMO; Multi-Input Multi-Output).Hereinafter, the usage of 2 antennae may be given as an example for themultiple antennae method, for simplicity in the description of thepresent invention. However, the description of the present invention maybe applied to a system using at least two or more antennae.

The SISO method refers to a general broadcasting system using 1transmission antenna and 1 reception antenna. And, the SIMO methodrefers to a broadcasting system using 1 transmission antenna andmultiple reception antennae.

The MISO method refers to a broadcasting system that can providetransmission diversity by using multiple transmission antennae andmultiple reception antennae. Herein, an example of the MISO method maycorrespond to an Alamouti method. The MISO method refers to a methodthat can receive antenna through 1 antenna without any performance loss.In the receiving system, the same data may be received through multiplereception antennae in order to enhance performance. However, in thiscase, such method will be described in the present invention while beingincluded within the range of the MISO.

Performances of systems employing MIMO depend on characteristics of atransmission channel and, particularly, systems having independentchannel environments exhibit high performance. That is, the performanceof a system to which MIMO is applied can be improved when channels fromantennas of a transmitter to antennas of a receiver are uncorrelated andindependent. However, in a channel environment in which correlationbetween channels between transmit antennas and receive antennas is high,such as a line-of sight (LOS) environment, the performance of a systememploying MIMO may abruptly decrease or the system may not operate.

When MIMO is applied to broadcast systems using single-inputsingle-output (SISO) and MISO schemes, a data transmission efficiencycan increase. However, the above-mentioned problems are generated andcompatibility should be maintained such that a receiver having a singleantenna can be provided with MIMO service. Accordingly, the presentinvention proposes a method capable of solving these problems.

Furthermore, the present invention proposes a broadcast signaltransceiver and a broadcast signal transmission/reception method for asystem capable of transmitting/receiving an additional broadcast signal(or enhanced broadcast signal), for example, a mobile broadcast signal,while sharing an RF band with a conventional terrestrial broadcastsystem, for example, DVT-T2.

To achieve this, the present invention can use a video coding methodhaving scalability, which can divide video components into a basic videocomponent having low definition while being robust against acommunication environment and a video component vulnerable to thecommunication environment while being capable of providing highdefinition images and respectively transmit the different types of videocomponents. While the present invention describes SVC as the videocoding method having scalability, other arbitrary video coding methodscan be used. Embodiments of the present invention will now be describedin detail with reference to the attached drawings.

A broadcast signal transmitter and receiver of the present invention canperform MISO processing and MIMO processing on a plurality of signalstransmitted and received through a plurality of antennas. A descriptionwill be given of a broadcast signal transceiver that processes twosignals transmitted and received through two antennas.

FIG. 1 illustrates a broadcast signal transmitter using the MIMO schemeaccording to an embodiment of the present invention.

As shown in FIG. 1, the broadcast signal transmitter according to thepresent invention may include an input processor 101100, an inputprocessing module 101200, a Bit Interleaved Coded Modulation (BICM)encoder 101300, a frame builder 101400, and an OrthogonalFrequency-Division Multiplexing (OFDM) generator (or transmitter)101500. The broadcast signal transmitter according to the presentinvention may receive a plurality of MPEG-TS streams or a General StreamEncapsulation (GSE) stream (or GS stream).

The input processor 101100 may generate physical layer pipes (PLPs) on aservice basis in order to give robustness to the input stream, that is,the plurality of MPEG-TS streams or the GSE stream.

Herein, the PLP corresponds to data unit being identified (orrecognized) in a physical layer, and the data are process in the sametransmission path for each PLP. More specifically, the PLP correspondsto data being processed in the transmission path, wherein the data havethe same physical layer characteristic. And, the PLP may be mapped incell units within a frame. Additionally, the PLP may also be consideredas a physical layer TDM (Time Division Multiplex) channel carrying oneor more multiple services. Accordingly, the path through which suchservice is being transmitted, or a stream unit that can be identified inthe physical layer and transmitted through such path will be referred toas a PLP.

The input processing module 101200 may generate a base band (BB) frameincluding the generated PLPs. The BICM encoder 101300 may add redundancyto the BB frame to correct an error on a transmission channel andinterleave PLP data included in the BB frame.

The frame builder 101400 may accomplish a transmission frame structureby mapping the plurality of PLPs to a transmission frame and addingsignaling information thereto. The OFDM generator 101500 may demodulateinput data from the frame builder according to OFDM to divide the inputdata into a plurality of paths such that the input data is transmittedthrough a plurality of antennas.

FIG. 2 illustrates an input processing module 101200 according to anembodiment of the present invention.

FIG. 2(A) show an embodiment of the input processing module 101200 whena single input stream is input to the input processing module 101200.When there is a single input stream, the input processing module 101200may include a mode adaptation block 102100 and a stream adaptation block102200.

The mode adaptation block 102100 may include an input interface module102110 for dividing the input bitstream into logical units for FEC(BCH/LDPC) encoding performed in a BICM encoder following the inputprocessing module 101200 and mapping the logical units, a cyclicredundancy check (CRC)-8 encoder 102120 for performing CRC encoding onthe mapped bitstream, and a BB header insertion unit 102130 forinserting a BB header having a fixed size to a data field. In this case,the BB header may include mode adaptation type (TS/GS/IP) information,user packet length information, data field length information, etc.

The stream adaptation block 102200 may include a padding insertion unit102210 for inserting a padding bit into the input bitstream toaccomplish one BB frame for FEC encoding when the input bitstream doesnot fill the BB frame, and a BB scrambler 102220 for generating a pseudorandom binary sequence (PRBS) and performing an XOR operation on theinput bitstream and the generated PRBS to randomizing the inputbitstream.

FIG. 2(B) illustrates another embodiment of the mode adaptation block102100 included in the input processing module 101200 when a pluralityof input streams is input to the input processing module 102100.

The mode adaptation block 102100 may include p+1 input interface modules102300-0 to 102300-p, p+1 input stream sync modules 102310-0 to102310-p, p+1 delay compensators 102320-0 to 102320-p, p+1 null packetcancellers 102330-0 to 1-2330-p, p+1 CRC encoders 102340-0 to 102340-p,and p+1 BB header insertion units 102350-0 to 102350-p.

P+1 input streams may be independently processed into streams convertedfrom a plurality of MPEG-TSs or GSE streams, and each of the processedstreams may be a complete stream including a plurality of servicecomponents or a stream of a minimum unit including only a single servicecomponent.

Paths through which the input streams to be independently processed aretransmitted may be referred to as PLPs. Services may betransmitted/received through a plurality of RF channels. PLP data may beincluded in slots distributed at time intervals in the plurality of RFchannels, or distributed at time intervals in one RF channel. Suchsignal frame may transmit time distributed (or time dispersed) PLPs toat least one RF channel. In other words, one PLP may be time distributedto one RF channel or multiple RF channels, thereby being transmitted.

To increase transmission efficiency, an embodiment of the presentinvention selects a PLP from the plurality of PLPs and transmitsinformation that can be commonly applied to the plurality of PLPsthrough the selected PLP. This PLP may be referred to as a common PLP orL2 signaling information. There may be multiple common PLPs according tothe intention of a designer. Furthermore, common PLP may be locatedfollowing L1 signaling information within a transmission frame.

The p+1 input interface modules 102300-0 to 102300-p, p+1 CRC encoders102340-0 to 102340-p, and p+1 BB header insertion units 102350-0 to102350-p have the same functions as those of the input interface module102100, CRC-8 encoder 102120, and BB header insertion unit 102130 shownin FIG. 2(A), and thus detailed descriptions thereof are omitted. Thep+1 input stream sync modules 102310-0 to 102310-p may insert inputstream clock reference (ISCR) information, that is, timing informationnecessary for a receiver to restore a transport stream (TS) or a genericstream (GS).

The p+1 delay compensators 102320-0 to 102320-p may acquiresynchronization by delaying data for PLPs in each group on the basis ofthe timing information inserted by the input stream sync modules, andthe p+1 null packet cancellers 102330-0 to 1-2330-p may deleteunnecessarily transmitted null packets inserted in delay-compensated BBframes and insert the number of deleted null packets to positions atwhich the null packets are deleted.

FIG. 3 illustrates the stream adaptation block included in the inputprocessing module according to another embodiment of the presentinvention.

The stream adaptation block 102200 shown in FIG. 3 may include ascheduler 103100 for performing scheduling for allocating a plurality ofPLPs to slots of a transport stream and transmitting L1-dynamicsignaling information of a current frame to the BICM encoder 101300,separately from in-band signaling, p+1 frame delays 103200-0 to 103211-pfor delaying input data by one frame such that the current frame caninclude scheduling information about the following frame for in-bandsignaling, p+1 in-band signaling/padding inserting units 103400-0 to103400-p for inserting undelayed L1-dynamic signaling information to thedata delayed by one frame and, when a padding space is present,inserting a padding bit to the padding space or inserting in-bandsignaling information to the padding space, and p+1 BB scramblers103400-0 to 103400-p. The p+1 BB scramblers 103400-0 to 103400-p operatein the same manner as the BB scrambler 102220 shown in FIG. 2(A), andthus detailed description thereof is omitted.

FIG. 4 illustrates the BICM encoder 101300 according to an embodiment ofthe present invention.

The BICM encoder 101300 may include a first BICM encoding block 104100and a second BICM encoding block 104200. The first BICM encoding block104100 may include blocks for respectively processing a plurality ofinput-processed PLPs, and the second BICM encoding block 104200 mayinclude blocks for respectively processing signaling information. Thesignaling information may include L1-pre signaling information andL1-post signaling information. Positions of the blocks may be changed bya designer. The blocks will now be described in detail.

The first BICM encoding block 104100 may include p+1 number of FECencoders 104110-0˜p configured to add a redundancy, so that thereceiving unit can correct an error occurring on a transmission channelwith respect to data including in the PLP (hereinafter referred to asPLP data), and to perform BCH encoding and LDPC encoding, p+1 number ofbit interleavers 1041200-0˜p configured to perform bit interleaving in asingle FEC block unit with respect to the PLP data being processed withFEC encoding, p+1 number of first demultiplexers 104130-0˜p configuredto perform demultiplexing on the bit-interleaved PLP data in single FECblock units, wherein the data reliability distribution being generatedduring the LDPC encoding process is dispersed in a later process, p+1number of constellation mappers 104140-0˜p configured to respectivelymap the demultiplexed bit unit PLP data to the constellation in symbolunits, p+1 number of second demultiplexers 104150-0˜p configured todivide the cells mapped to the constellation to 2 paths, i.e., to afirst path and a second path, and to output the divided cells throughthe respective path, p+1 number of cell interleavers 1041600-0˜pconfigured to perform interleaving in cell units on the PLP data beingmapped to the constellation, p+1 number of time interleavers 104170-0˜pconfigured to perform interleaving in time units on the cell-interleavedPLP data, and p+1 number of constellation rotators/re-mappers 104180-0˜pconfigured to remap bit unit bit unit PLP data being inputted throughthe first path and the second path to the constellation in symbol units,and configured to rotate the constellation to a predetermined angle (ordegree) in accordance with the modulation type.

The first BICM encoding block 104100 may include a MISO encoder or aMIMO encoder for performing MISO encoding or MIMO encoding for theplurality of PLPs. In this case, The MISO/MIMO encoder may follow thep+1 constellation mappers 104140-0 to 104140-p or follow the p+1 timeinterleavers 104170-0 to 104170-p. Otherwise, the MISO/MIMO encoder maybe included in the OFDM generator 101500.

Data output through the first path divided by the p+1 seconddemultiplexers 104150-0 to 104150-p may be transmitted through a firstantenna Tx_1 and data output through the second path may be transmittedthrough a second antenna Tx_(—)2.

The constellations rotated by the p+1 constellation rotators/remappers104180-0 to 104180-p may be represented by an in-phase (I-phase)component and a quadrature-phase (Q-phase) component. The p+1constellation rotators/remappers 104180-0 to 104180-p may delay only theQ-phase component by a predetermined value. Then, the p+1 constellationrotators/remappers 104180-0 to 104180-p may remap the interleaved PLPdata to new constellations using the I-phase component and the delayedQ-phase component. Accordingly, a diversity gain can be obtained sinceI/Q components of the first and second paths are mixed and thus the sameinformation is transmitted through the first and second paths. The p+1constellation rotators/remappers 104180-0 to 104180-p may be locatedbefore the cell interleavers, which can be changed by the designer.Consequently, the first BICM encoding block 104100 can output two piecesof data for each PLP. For example, the first BICM encoding block 104100can receive PLP0, process received PLP0 and output STX_(—)0 andSTX_(—)0+1. In this case, multiple PLPs may be included in the baselayer and enhancement layer of a broadcast service, which is processedby using the SVC method. And, herein, the multiple PLPs may includenetwork information, such as an NIT (Network Information Table), or PLPinformation, and may also include service information such as an SDT(Service Description Table), an EIT (Event Information Table), and a PMT(Program Map Table)/PAT (Program Association Table), and, among themultiple PLPs, only a specific PLP may include the service information.This is a feature that may be varied or modified depending upon theintentions of the system designer. Therefore, a respective broadcastsignal receiver may decode all of the multiple PLPs or may decode only aspecific PLP, so as to acquire service information, thereby beingcapable of receiving a desired (or wanted) broadcast service.

The second BICM encoding block 104200 may include an L1 signalinggenerator 104210 for encoding input L1-dynamic information andL1-configurable information to generate L1-pre signaling information andL1-post signaling information, two FEC encoders, a bit interleaver, ademultiplexer, two constellation mappers, two dividers, and twoconstellation rotators/remappers.

The L1 signaling generator 104210 may be included in the streamadaptation block 102200 described in FIG. 2 and FIG. 3, which may bechanged by the designer. Other blocks operate in the same manner asthose included in the first BICM encoding block 104100, and thusdetailed description thereof is omitted.

The L1-pre signaling information may include information necessary forthe receiver to decode the L1-post signaling information, and theL1-post signaling information may include information necessary for thereceiver to restore received data. To decode L1-signaling informationand data in the receiver, correct and rapid decoding of the L1-presignaling information is necessary. Accordingly, the second BICMencoding block 104200 according to the present invention does notperform bit interleaving and demultiplexing on the L1-pre signalinginformation such that the receiver can rapidly decode the L1-presignaling information. Consequently, the second BICM encoding block104200 can output two pieces of data for the L-dynamic information andL1-configurable information. For example, the first BICM encoding block104100 can receive and process the L1-dynamic information and outputSTX-pre and STX_pre+1.

The BICM encoder 101300 may process the data input through the first andsecond paths and output the processed data to the frame builder 101400through the first and second paths. This may be changed according to theintention of the designer.

FIG. 5 illustrates the frame builder 101400 according to an embodimentof the present invention.

As described above, the first BICM encoding block 104100 can output twodata such as STX_k and STX_k+1 for a plurality of PLP data and thesecond BICM encoding block 104200 can output four signaling data, thatis, STX_pre, STX_pre+1, STX_post and STX_post+1 for the L-pre signalinginformation and the L1-post signaling information.

Each output data is input to the frame builder 101400. In this case, asshown in FIG. 5, the frame builder 101400 may receive the four signalingdata, that is, STX_pre, STX_pre+1, STX_post and STX_post+1 first fromamong the data output from the BICM encoder 101300. The frame builder104100 may include a delay compensator 105100 for compensating a delayof one transmission frame and a delay according to processing in theBICM encoding module 101300 for the L1-pre signaling data or the L1-postsignaling data, a cell mapper 105200 for arranging input common PLPcells, PLP cells including normal data and cells including signalinginformation in an OFDM symbol based array of a transmission frame usingscheduling information, and a frequency interleaver 105300 forinterleaving cells input thereto in the frequency domain and outputtingthe interleaved data through first and second paths.

The cell mapper 1054200 may include a common PLP assembler, sub-sliceprocessor, data PLP assembler and signaling information assembler blocksand perform an arrangement-related function using scheduling informationincluded in signaling information. The cell mapper 105200 may apply thesame cell mapping scheme or different cell mapping schemes to the firstand second paths depending on the scheduling information.

The frame builder 101400 may process data input through the first andsecond paths and output the processed data to the OFDM generator throughthe first and paths, which may be changed according to the intention ofthe designer.

FIG. 6 illustrates the OFDM generator 101500 according to an embodimentof the present invention.

The OFDM generator 101500 according to an embodiment of the presentinvention may receive broadcast signals through first and second paths,demodulates the received broadcast signals and output the demodulatedsignals to two antennas TX1 and TX2. The OFDM generator 101500 may bereferred to as a transmission unit.

In the present invention, a block for modulating the broadcast signal tobe transmitted through the first antenna TX1 may be referred to as afirst OFDM generating unit 106100 and a block for modulating thebroadcast signal to be transmitted through the second antenna TX2 may bereferred to as a second OFDM generating unit 106200.

When channel correlation between channels transmitted through the firstand second antennas is high, the first and second antennas may apply apolarity to transmitted signals according to the sign of the correlationand transmit the signals. A MIMO scheme using this technique may bereferred to as a polarity multiplexing MIMO scheme, the first antennathat adds a polarity to a received signal and transmits the signal withthe polarity may be referred to as a vertical antenna, and the secondantenna that adds a polarity to a received signal and transmits thesignal with the polarity may be referred to as a horizontal antenna. Adescription will be given of modules included in the first OFDMgenerating unit 106100 and the second OFDM generating unit 106200.

The first OFDM generating unit 106100 may include a MISO encoder 10610for MISO-encoding input symbols transmitted through each path such thatthe input symbols have transmit diversity, a pilot insertion module106120 for inserting a pilot having a predetermined pilot pattern into apredetermined position in a transmission frame and outputting thetransmission frame to an inverse fast Fourier transform (IFFY) module106130, the IFFY module 106130 performing IFFY on the signal having thepilot on each path, a peak-to-average power ratio (PAPR) module 106140for reducing a PAPR of signals in the time domain and outputting thesignals with the reduced PAPR to a guard interval (GI) insertion module106150 or feeding back necessary information to the pilot insertionmodule 106120 according to a PAPR reduction algorithm, the GI insertionmodule 106150 copying the last part of an effective OFDM symbol,inserting a GI into each OFDM symbol in the form of a cyclic prefix (CP)and outputting each OFDM symbol to a P1 symbol insertion module 106160,the P1 symbol insertion module 106160 inserting a P1 symbol into thebeginning of each transmission frame, and a digital-to-analog converter(DAC) module 106170 converting each signal frame having the P1 symbolinserted thereto into an analog signal and transmitting the analogsignal through the first antenna Tx1.

Additionally, depending upon the intentions of the system designer, theMISO encoder 106110 may perform processing on the inputted symbols byusing at least one of the MIMO, MISO, and SISO methods. In this case,the MISO encoder 106110 may perform an overall MIMO encoding process onthe multiple PLP data, or the MISO encoder 106110 may perform MISOencoding on a portion of the PLP data, and the MISO encoder 106110 mayperform MISO encoding on the signaling data. Furthermore, the MISOencoder 106110 may also perform a dual SISO encoding process on thesignaling data.

Moreover, depending upon the intentions of the system designer, the MISOencoder 106110 may be included in front of the first OFDM generatingunit 106100, instead of being included in the first OFDM generating unit106100.

The second OFDM generating unit 106200 may include the same modules asthose of the first OFDM generating unit 106100. The modules included inthe second OFDM generating unit 106200 perform the same functions asthose of the modules included in the first transmitter 106100, and thusdetailed descriptions are omitted.

FIG. 7 illustrates a broadcast signal receiver according to anembodiment of the present invention.

As shown in FIG. 7, the broadcast signal receiver may include an OFDMdemodulator 107100, a frame demapper 107200, a BICM decoder 107300, andan output processor 107400. The OFDM demodulator (or OFDM demodulationunit or reception unit) 107100 may convert signals received through aplurality of receive antennas into signals in the frequency domain. Theframe demapper 107200 may output PLPs for a necessary service from amongthe converted signals. The BICM decoder 107300 may correct an errorgenerated according to a transmission channel. The output processor107400 may perform procedures necessary to generate output TSs or GSs.Here, dual polarity signals may be input as input antenna signals andone or more streams may be output as the TXs or GSs.

FIG. 8 illustrates the OFDM demodulator 108100 according to anembodiment of the present invention.

The OFDM demodulator 108100 may receive broadcast signals of therespective paths through two antennas Rx1 and Rx2 and perform OFDMdemodulation on the broadcast signals. A block that demodulates thebroadcast signal received through the first antenna Rx1 may be referredto as a first OFDM demodulating unit 108100 and a block that demodulatesthe broadcast signal received through the second antenna Rx2 may bereferred to as a second OFDM demodulating unit 108200. Furthermore,according to an embodiment of the present invention, polaritymultiplexing MIMO can be employed. That is, the first OFDM demodulatingunit 108100 may demodulate the broadcast signal input through the firstantenna Rx1 according to OFDM and output the demodulated broadcastsignal to the frame demapper 107200 through a first path, and the secondOFDM demodulating unit 108200 may demodulate the broadcast signal inputthrough the second antenna Rx2 according to OFDM and output thedemodulated broadcast signal to the frame demapper 107200 through asecond path.

The first OFDM demodulating unit 108100 may include an ADC module108110, a P1 symbol detection module 108120, a synchronization module108130, a GI cancellation module 108140, an FFT module 108150, a channelestimation module 108160, and a MISO decoder 108170.

The second OFDM demodulating unit 108200 may include modules identicalto the modules of the first OFDM demodulating unit 108100 and themodules included in the second OFDM demodulating unit 108200 perform thesame functions as the modules included in the first OFDM demodulatingunit 108100.

Additionally, depending upon the intentions of the system designer, theMISO decoder 108170 may perform processing on the inputted data by usingat least one of the MIMO, MISO, and SISO methods. In this case, the MISOdecoder 108170 may perform an overall MIMO decoding process on themultiple PLP data, or the MISO decoder 108170 may perform MISO decodingon a portion of the PLP data, and the MISO decoder 108170 may onlyperform a MISO encoding process on the signaling data, so as to output atransmission frame. Furthermore, the MISO decoder 108170 may alsoperform a dual SISO decoding process on the signaling data.

Moreover, depending upon the intentions of the system designer, the MISOdecoder 108170 may be included in front of the first OFDM demodulatingunit 106100, instead of being included in the first OFDM demodulatingunit 106100.

The OFDM demodulator 107100 shown in FIG. 8 can perform a reverseprocedure of the procedure of the OFDM generator 101500 illustrated inFIG. 6, and thus detailed description thereof is omitted.

FIG. 9 illustrates the frame demapper 107200 according to an embodimentof the present invention.

As shown in FIG. 9, the frame demapper 107200 may include a frequencydeinterleaver 109100 for processing data input through the first andsecond paths and a cell mapper 109200. This may be modified by thedesigner. The frame demapper 107200 shown in FIG. 9 can perform areverse procedure of the procedure of the frame builder 101400illustrated in FIG. 5 and thus detailed description thereof is omitted.

FIG. 10 illustrates the BICM decoder 107300 according to an embodimentof the present invention.

Referring to FIG. 10, the BICM decoder 107300 may include a first BICMdecoding block 110100 for processing data SRx_(—)0 to SRx_P+1 outputthrough the first and second paths from the frame demapper 107200 and asecond BICM decoding block 110200 for processing data SRx_pre toSRx_post+1 output through the first and second paths. In this case, p+1constellation demappers 110110-0 to 110110-p included in the first BICMdecoding block 110100 and two constellation demappers 110210-0 and110210-1 included in the second BICM decoding block 110200 may rotateconstellations by a predetermined angle, delay only Q-phase componentsof the constellations by a predetermined value and calculate LLR valuesin consideration of the constellation rotation angle. If constellationrotation and Q-phase component delay are not performed, the LLR valuescan be calculated on the basis of normal QAM. The p+1 constellationdemappers 110110-0 to 110110-p included in the first BICM decoding block110100 and the two constellation demappers 110210-0 and 110210-1included in the second BICM decoding block 110200 may be located beforethe cell interleaver, which may be modified by the designer.

The BICM decoder 107300 according to the present invention may include aMISO decoder or a MIMO decoder according to the intention of thedesigner. In this case, the MISO decoder or the MIMO decoder may followthe cell interleaver or the constellation demappers. This may bemodified according to the designer.

Additionally, depending upon the intentions of the system designer, theBICM decoder 107300 according to the present invention may also includean MISO decoder or an MIMO decoder. In this case, the MISO decoder orthe MIMO decoder may be positioned after the cell interleaver, or may beplaced after the constellation demapper. Herein, the position of theMISO decoder or the MIMO decoder may be varied depending upon theintentions of the system designer.

Additionally, the BICM decoder 107300 according to the present inventionmay refer to a single block including a first BICM decoding block 110100and a second BICM decoding block 110200. Alternatively, each of thefirst BICM decoding block 110100 and the second BICM decoding block110200 may also be referred to as an independent decoder. This may bevaried depending upon the intentions of the system designer. Therefore,when the second BICM decoding block 110100 decodes the signalinginformation, the first BICM decoding block 110200 uses the decodedsignaling information so as to identify and decode a PLP including awanted (or desired) service or service component.

The p+1 number of first multiplexers 110120-0˜p and 2 first multiplexers110220-0˜p, shown in FIG. 10, may merge the cell being separatelytransmitted through the first path and the second path to a single cellstream.

Other blocks included in the BICM decoder 107300 may perform a reverseprocedure of the procedure of the BICM encoder illustrated in FIG. 4 andthus detailed description thereof is omitted.

FIG. 11 illustrates the output processing module 107500 of the broadcastsignal receiver according to an embodiment of the present invention.

The output processing module 107500 shown in FIG. 11(A) corresponds tothe input processing module 101100 for processing a single PLP,illustrated in FIG. 1(A), and performs a reverse procedure of theprocedure of the input processing module 101100. The output processingmodule 107500 may include a BB descrambler 111100, a padding removalmodule 111110, a CRC-8 decoder 111120 and a BB frame processor 111130.The output processing module 107500 shown in FIG. 11(A) may receive abitstream from the BICM decoder 107300 (or decoding module) of thebroadcast signal receiver, which performs a reverse procedure of theBICM encoding procedure of the broadcast signal transmitter and performsa reverse procedure of the procedure of the input processing module101200 illustrated in FIG. 1, and thus detailed description thereof isomitted.

FIG. 11(B) illustrates the output processing module 107500 of thebroadcast signal receiver according to another embodiment of the presentinvention. The output processing module 107500 shown in FIG. 11(B) maycorrespond to the input processing module 101200 for processing aplurality of PLPs, illustrated in FIG. 2(B), and perform a reverseprocedure of the procedure of the input processing module 101200. Theoutput processing module 107500 shown in FIG. 11(B) may include aplurality of blocks for processing a plurality of PLPs. Specifically,the output processing module 107500 may include p+1 BB descramblers, p+1padding removal modules, p+1 CRC-8 decoders, p+1 BB frame processors,p+1 de-jitter buffers 111200-0 to 111200-p for compensating a delayinserted by the broadcast signal transmitter for synchronization of theplurality of PLPs according to time to output (TTO) parameterinformation, p+1 null packet insertion modules 111210-0 to 111210-p forrestoring null packets cancelled by the transmitter with reference todeleted null packet (DNP) information, a TS clock regeneration module111220 for restoring detailed time synchronization of output packets onthe basis of input stream time reference (ISCR) information, an in-bandsignaling decoder 111240 for restoring and outputting in-band signalinginformation transmitted through padding bit fields of data PLPs, and aTS recombining module 111230 for receiving data PLPs related to arestored common PLP and restoring original TSs, IPs or GSs. The outputprocessing module 107500 shown in FIG. 11(B) may include an L1 signalingdecoder (not shown). Descriptions of the blocks corresponding to theblocks shown in FIG. 11(A) are omitted.

Processing of the plurality of PLPs according to the broadcast signalreceiver may be described for a case in which data PLPs related to acommon PLP are decoded or a case in which the broadcast signal receiversimultaneously decodes a plurality of services or service components(e.g. components of scalable video service (SVS)). The BB descramblers,padding removal modules, CRC-8 decoders and BB frame processorscorrespond to those illustrated in FIG. 11(A).

FIG. 12 illustrates an additional frame structure based on PLP accordingto an embodiment of the present invention.

As shown in FIG. 12, a frame according to an embodiment of the presentinvention may include a preamble area and a data area. The preamble areamay include a P1 symbol and a P2 symbol and the data area may include aplurality of data symbols.

The P1 symbol may transmit P1 signaling information associated with abasic transmission parameter and transmission type and a correspondingpreamble identifier and the receiver may detect the frame using the P1symbol. A plurality of P2 symbols may be provided and may carry L1signaling information and signaling information such as a command PLP.The common PLP may include network information such as a NetworkInformation Table (NIT), PLP information, and service information suchas a Service Description Table (SDT) or an Event Information Table(EIT).

A plurality of data symbols located next to the P1 symbol may include aplurality of PLPs. The plurality of PLPs may include audio, video, anddata TS streams and PSI/SI information such as a Program AssociationTable (PAT) and a Program Map Table (PMT). In the present invention, aPLP that transmits PSI/SI information may be referred to as a base PLPor a signaling PLP. The PLPs may include a type-1 PLP that istransmitted through one sub-slice per frame and a type-2 PLP that istransmitted through two sub-slices per frame. The plurality of PLPs maytransmit one service and may also transmit service components includedin one service. When the PLPs transmit service components, thetransmitting side may transmit signaling information which indicatesthat the PLPs transmit service components.

In addition, additional data (or an enhanced broadcast signal) inaddition to basic data may be transmitted through a specific PLP whilesharing an RF frequency band with the conventional terrestrial broadcastsystem according to an embodiment of the present invention. In thiscase, the transmitting side may define a system or a signal that iscurrently transmitted through signaling information of the P1 symboldescribed above. The following description is given with reference tothe case in which the additional data is video data. That is, as shownin FIG. 12, PLP M1 112100 and PLP (M1+M2) 112200 which are type 2 PLPsmay be transmitted while including additional video data. In addition,in the present invention, a frame that transmits such additional videodata may be referred to as an additional transmission frame.Furthermore, in addition to transmitting additional video data dependingupon the intentions of the system designer, an additional transmissionframe may also transmit data related to a new broadcasting system otherthan the related art terrestrial broadcasting system.

FIG. 13 illustrates a structure of an FEF based an additionaltransmission frame according to an embodiment of the present invention.

Specifically, FIG. 13 shows the case in which a Future Extension Frame(FEF) is used in order to transmit additional video data. In the presentinvention, a frame that transmits basic video data may be referred to asa basic frame and an FEF that transmits additional video data may bereferred to as a additional transmission frame.

FIG. 13 shows structures of superframes 11100 and 113200 in each ofwhich a basic frame and additional transmission frame are multiplexed.Frames 113100-1 to 113100-n that are not shaded from among framesincluded in the superframe 113100 are basic frames and shaded frames113120-1 and 113120-2 are additional transmission frames.

FIG. 13(A) shows the case in which the ratio of basic frames toadditional transmission frames is N:1. In this case, the time requiredfor the receiver to receive a next additional transmission frame113120-2 after receiving one additional transmission frame 113120-1 maycorrespond to N basic frames.

FIG. 13(B) shows the case in which the ratio of basic frames toadditional transmission frames is 1:1. In this case, the proportion ofadditional transmission frames in the superframe 113200 may be maximizedand therefore the additional transmission frames may have a structurevery similar to that of the basic frames in order to maximize the extentof sharing with the basic frames. In addition, in this case, the timerequired for the receiver to receive a next additional transmissionframe 113210-2 after receiving one additional transmission frame113210-1 corresponds to 1 basic frame 113220 and therefore thesuperframe period is shorter than that of FIG. 13(A).

FIG. 14(A) and FIG. 14(B) illustrate a P1 symbol generation procedurefor identifying additional frames according to an embodiment of thepresent invention.

In the case in which additional video data is transmitted throughadditional frames which are distinguished from basic frames as shown inFIG. 13, there is a need to transmit additional signaling informationfor enabling the receiver to identify and process an additional frame.An additional frame of the present invention may include a P1 symbol fortransmitting such additional signaling information and the P1 symbol maybe referred to as a new_system_P1 symbol. This new_system_P1 symbol maybe different from a P1 symbol that is used in a conventional frame and aplurality of new_system_P1 symbols may be provided. In an embodiment,the new_system_P1 symbol may be located before a first P2 symbol in apreamble area of the frame.

The present invention may modify the P1 symbol of a conventionaltransmission frame and use the modified P1 symbol in order to generatethe new_system_P1 symbol. To achieve this, the present inventionproposes a method of generating the new_system_P1 symbol by modifyingthe P1 symbol structure of the conventional transmission frame ormodifying a symbol generator 114100.

FIG. 14(A) shows the P1 symbol structure of the conventionaltransmission frame. In the present invention, it is possible to modifythe PI symbol structure of the conventional transmission frame shown inFIG. 14(A) to generate the new_symbol_P1 symbol. In this case, thenew_system_P1 symbol may be generated by changing frequency shift valuesf_SH for prefix and post fix of the conventional P1 symbol or bychanging the duration (T_P1C or T_P1B) of the P1 symbol. However, whenthe P1 symbol structure is modified to generate an new_system_P1 symbol,parameters f_SH, T_P1C and T_P1B used for the P1 symbol structure needto be appropriately modified.

FIG. 14(B) illustrates a P1 symbol generator for generating a P1 symbol.The present invention may generate the new_system_P1 symbol by modifyingthe P1 symbol generator shown in FIG. 14(B). In this case, it ispossible to generate the new_system_P1 symbol using a method of changinga distribution of active carriers used for a P1 symbol in a CDS tablemodule 114110, an MSS module 114120 and a C-A-B structure module 114130included in the P1 symbol generator 114100 (e.g. the CDS table module114110 uses a different complementary set of sequence (CSS)) or a methodof changing a pattern for information transmitted through the P1 symbol(e.g. the MSS module 114120 uses a different CSS).

FIG. 15 shows L1-pre signaling information according to an embodiment ofthe present invention.

As described above, L1 signaling information may include L1-presignaling information and L1-post signaling information.

FIG. 15 shows an embodiment of a table included in the L1-pre signalinginformation. The L1-pre signaling information may include informationnecessary to receive and decode the L1-post signaling information.Fields included in the table will now be described. The size of eachfield and field types that can be included in the table may be changed.

The TYPE field has 8 bits and may indicate whether the type of an inputstream is TS or GS.

The BWT_EXT field has 1 bit and may indicate bandwidth extension of anOFDM symbol.

The S1 field has 3 bits and may represent whether a current transmissionsystem is a MISO system or a MIMO system.

The S2 field has 4 bits and may indicate an FFT size.

The L1_REPETITION FLAG field has 1 bit and may represent a repetitionflag of an L1 signal.

The GUARD_Interval field has 3 bits and may indicate the size of a guardinterval of the current transmission system.

The PAPR field has 4 bits and may indicate a PAPR reduction scheme. Asdescribed above, ACE or TR scheme may be used as the PAPR scheme in thepresent invention.

The L1_MOD field has 4 bits and may indicate QAM modulation type of theL1-post signaling information.

The L1_COD field has 2 bits and may indicate the code rate of theL1-post signaling information.

The L1_FEC_TYPE field has 2 bits and may indicate the FEC type of theL1-post signaling information.

The L1_POST_SIZE field has 18 bits and may indicate the size of theL1-post signaling information.

The L1_POST_INFO_SIZE field has 18 bits and may indicate the size of aninformation region of the L1-post signaling information.

The PILOT_PATTERN field has 4 bits and may indicate a pilot insertionpattern.

The TX_ID_AVAILABILITY field has 8 bits and may indicate transmitteridentification availability in a current geographical cell range.

The CELL_ID field has 16 bits and may indicate a cell identifier.

The NETWORK_ID field has 16 bits and may indicate a network identifier.

The SYSTEM_ID field has 16 bits and may indicate a system identifier.

The NUM_FRAMES field has 8 bits and may indicate the number oftransmission frames per super-frame.

The NUM_DATA_SYMBOLS field 12 bits and may indicate the number of OFDMsymbols per transmission frame.

The REGEN_FLAG field has 3 bits and may indicate the number ofregenerations of a signal according to a repeater.

The L1_POST_EXTENSION field has 1 bit and may indicate presence orabsence of an extension block of the L1-post signaling information.

The NUM_RF field has 3 bits and may indicate the number of RF bands forTFS.

The CURRENT_RF_IDX field has 3 bits and may indicate the index of acurrent RF channel.

The RESERVED field has 10 bits and is reserved for later use.

The CRC_(—)32 field has 32 bits and may indicate a CRC error extractioncode of the L1-pre signaling information.

FIG. 16 shows L1-post signaling information according to an embodimentof the present invention.

The L1-post signaling information may include parameters necessary forthe receiver to encode PLP data.

The L1-post signaling information may include a configurable block, adynamic block, an extension block, a cyclic redundancy check (CRC)block, and an L1 padding block.

The configurable block may include information equally applied to onetransmission frame and the dynamic block may include characteristicinformation corresponding to a currently transmitted frame.

The extension block may be used when the L1-post signaling informationis extended, and the CRC block may include information used for errorcorrection of the L1-post signaling information and may have 32 bits.The padding block may be used to adjust sizes of informationrespectively included in a plurality of encoding blocks to be equal whenthe L1-post signaling information is transmitted while being dividedinto the encoding blocks and has a variable size.

FIG. 16 shows a table included in the configurable block, which includesthe following fields. The size of each field and field types that can beincluded in the table are variable.

The SUB_SLICES_PER_FRAME field has a size of bits and may indicate thenumber of sub-slices per transmission frame.

The NUM_PLP field has a size of 8 bits and may indicate the number ofPLPs.

The NUM_AUX field has a size of 4 bits and may indicate the number ofauxiliary streams.

The AUX_CONFIG_RFU field has a size of 8 bits and is a reserved region.

The following fields are included in a frequency loop.

The RF_IDX field has a size of 3 bits and may indicate an RF channelindex.

The FREQUENCY field has a size of 32 bits and may indicate an RF channelfrequency.

The following fields are used only when the LSB of S2 field is 1, thatis, when S2=‘xxx1’.

The FEF_TYPE field has a size of 4 bits and may be used to indicate afuture extension frame (FEF).

The FEF_LENGTH field has a size of 22 bits and may indicate the lengthof an FEF.

The FEF_INTERVAL field has a size of 8 bits and may indicate theduration of an FEF interval.

The following fields are included in a PLP loop.

The PLP_ID field has a size of 8 bits and may be used to identify a PLP.

The PLP_TYPE field has a size of 3 bits and may indicate whether acurrent PLP is a common PLP or a PLP including normal data.

The PLP_PAYLOAD_TYPE field has a size of 5 bits and may indicate a PLPpayload type.

The FF_FLAG flag has a size of 1 bit and may indicate a fixed frequencyflag.

The FIRST_RF_IDX field has a size of 3 bits and may indicate the indexof the first RF channel for TFS.

The FIRST FRAME IDX field has a size of 8 bits and may indicate thefirst frame index of a current PLP in a super-frame.

The PLP_GROUP_ID field has a size of 8 bits and may be used to identifya PLP group. A PLP group may be referred to as a link-layer-pipe (LLP)and PLP_GROUP_ID field is called LLP_ID field in an embodiment of thepresent invention.

The PLP_COD field has a size of 3 bits and may indicate a code rate of aPLP.

The PLP_MOD field has a size of 3 bits and may indicate a QAM type of aPLP.

The PLP_ROTATION field has a size of 1 bit and may indicate aconstellation rotation flag of a PLP.

The PLP_FEC_TYPE field has a size of 2 bits and may indicate FEC type ofa PLP.

The PLP_NUM_BLOCKS_MAX field has a size of 10 bits and may indicate amaximum number of PLPs of FEC blocks.

The FRAME_INTERVAL field has a size of 8 bits and may indicate aninterval of a transmission frame.

The TIME_IL_LENGTH field has a size of 8 bits and may indicate a symbolinterleaving (or time interleaving) depth.

The TIME_IL_TYPE field has a size of 1 bit and may indicate a symbolinterleaving (or time interleaving) type.

The IM-BAND_B_FLAG field has a size of 1 bit and may indicate an in-bandsignaling flag.

The RESERVED_(—)1 field has a size of 16 bits and is used in the PLPloop in the future.

The RESERVED_(—)2 field has a size of 32 bits and is used in theconfigurable block in the future.

The following fields are included in an auxiliary stream loop.

The AUX_RFU field has a size of 32 bits and may be used in the auxiliarystream loop in the future.

FIG. 17 shows L1-post signaling information according to anotherembodiment of the present invention.

A table shown in FIG. 17 is included in the dynamic block and includesthe following fields. The size of each field and field types that can beincluded in the table are variable.

The FRAME_IDX field has a size of 8 bits and may indicate a frame indexin a super-frame.

The SIB_SLICE_INTERVAL field has a size of 22 bits and may indicate asub-slice interval.

The TYPE_(—)2_START field has a size of 22 bits and may indicate a startposition of PLPs of a symbol interleaver over a plurality of frames.L1_CHANGE_COUNTER field has a size of 8 bits and may indicate a changein L1 signaling.

The START_RF_IDX field has a size of 3 bits and may indicate a start RFchannel index for TFS.

The RESERVED_(—)1 field has a size of 8 bits and is a reserved field.

The following fields are included in the PLP loop.

The PLP_ID field has a size of 8 bits and may be used to identify eachPLP.

The PLP_START field has a size of 22 bits and may indicate a PLP startaddress in a frame.

The PLP_NUM_BLOCKS field has a size of 10 bits and may indicate thenumber of PLPs of FEC blocks.

The RESERVED_(—)2 field has a size of 8 bits and may be used in the PLPloop in the future.

The RESERVED_(—)3 field has a size of 8 bits and may be used in thedynamic block in the future.

The following field is included in the auxiliary stream loop.

The AUX_RFU field has a size of 48 bits and may be used in the auxiliarystream loop in the future.

In addition, the present invention proposes a MIMO system using scalablevideo coding (SVC). SVC is a video coding method developed to cope witha variety of terminals and communication environments and variations inthe terminals and communication environments. SVC can code a videohierarchically such that desired definition is generated and transmitadditional video data having a base layer from which video data about animage having basic definition can be restored and an enhancement layerfrom which an image having higher definition can be restored.Accordingly, a receiver can acquire the basic definition image byreceiving and decoding only the video data of the base layer, or obtainthe higher definition image by decoding the video data of the base layerand the video data of the enhancement layer according to characteristicsthereof. In the following description, the base layer can include videodata corresponding to the base layer and the enhancement layer caninclude video data corresponding to the enhancement layer. In thefollowing, video data may not be a target of SVC, the base layer caninclude data capable of providing a fundamental service including basicvideo/audio/data corresponding to the base layer, and the enhancementlayer can include data capable of providing a higher service includinghigher video/audio/data corresponding to the enhancement layer.

The present invention proposes a method of transmitting the base layerof SVC through a path through which signals can be received according toSISO or MISO using SVC and transmitting the enhancement layer of SVCthrough a path through which signals can be received according to MIMOin the broadcast system of the present invention. That is, the presentinvention provides a method by which a receiver having a single antennaacquires an image with basic definition by receiving the base layerusing SISO or MISO and a receiver having a plurality of antennasacquires an image with higher definition by receiving the base layer andthe enhancement layer using MIMO.

FIG. 18 illustrates a MIMO broadcast signal transmitter and atransmission method using SVC according to a first embodiment of thepresent invention.

Referring to FIG. 18, the broadcast signal transmitter may include anSVC encoder 120100 for encoding a broadcast service using SVC, and aMIMO encoder 120200 for distributing data according to a space diversityor space multiplexing scheme such that the data can be transmittedthrough a plurality of antennas. The broadcast signal transmitter shownin FIG. 18 uses hierarchical modulation.

The SVC encoder 120100 encodes a broadcast service and outputs a baselayer and an enhancement layer. The base layer is transmitted as thesame data through a first antenna (Ant1) 120300 and a second antenna(Ant2) 120400. The enhancement layer is encoded by the MIMO encoder120200 and transmitted as the same data or different data through thefirst and second antennas 120300 and 120400. In this case, thetransmitter performs symbol mapping during data modulation, which isshown in the left of FIG. 18 (a symbol mapper is not shown).

The broadcast signal transmitter may map bits corresponding to the baselayer to the MSB of data modulated during symbol mapping and map bitscorresponding to the enhancement layer to the LSB of the data byperforming hierarchical modulation.

FIG. 19 illustrates a MIMO broadcast signal transmitter and atransmission method using SVC according to a second embodiment of thepresent invention.

Referring to FIG. 19, the broadcast signal transmitter may include anSVC encoder 121100 for encoding a broadcast signal using SVC, and a MIMOencoder 121200 for distributing data according to a space diversity orspace multiplexing scheme such that the data can be transmitted througha plurality of antennas. The broadcast signal transmitter shown in FIG.19 uses frequency division multiplexing (FDM).

The SVC encoder 121100 encodes a broadcast service and outputs a baselayer and an enhancement layer. The base layer is transmitted as thesame data through a first antenna (Ant1) 121300 and a second antenna(Ant2) 121400. The enhancement layer is encoded by the MIMO encoder121200 and transmitted as the same data or different data through thefirst and second antennas 121300 and 121400.

The broadcast signal transmitter may process data using FDM in order toimprove data transmission efficiency and, particularly, may transmitdata through a plurality of subcarriers using OFDM. In addition, thebroadcast signal transmitter may classify subcarriers into subcarriersused to transmit SISO/MISO signals and subcarriers used to transmit MIMOsignals and transmit the signals using the subcarriers. The base layeroutput from the SVC encoder 121100 may be transmitted through theplurality of antennas using SISO/SISO carriers, whereas the enhancementlayer may be MIMO-encoded and then transmitted through the plurality ofantennas using MIMO carriers.

A broadcast signal receiver may receive OFDM symbols, acquire the baselayer by decoding data corresponding to the SISO/MISO carriers andacquire the enhancement layer by MIMO-decoding data corresponding to theMIMO carriers. Then, the service may be restored and provided using onlythe base layer when MIMO decoding cannot be performed, and using boththe base layer and the enhancement layer when MIMO decoding can beperformed according to channel state and reception system. In the secondembodiment, since bit information of a service is subjected to MIMOprocessing after mapped to symbols, the MIMO encoder 121200 can belocated after the symbol mapper so as to simplify the configuration ofthe broadcast signal transmitter than that of the broadcast signaltransmitter shown in FIG. 19.

FIG. 20 illustrates a MIMO broadcast signal transmitter and transmissionmethod using SVC according to a third embodiment of the presentinvention.

Referring to FIG. 20, the broadcast signal transmitter may include anSVC encoder 122100 for encoding a broadcast service using SVC and a MIMOencoder 122200 for distributing data through space diversity or spacemultiplexing such that the data can be transmitted through a pluralityof antennas. The broadcast signal transmitter shown in FIG. 20 uses timedivision multiplexing (TDM).

In the embodiment shown in FIG. 20, the broadcast signal transmitter mayrespectively transmit a base layer and an enhancement layer encodedaccording to SVC through SISO/MISO slots and MIMO slots. These slots maybe time or frequency slots and they are time slots in the embodimentshown in FIG. 20. Otherwise, the slots may be PLPs. A broadcast signalreceiver checks the type of received slots, receives the base layer fromSISO/MISO slots and receives the enhancement layer from MIMO slots. Asdescribed above, the receiver may restore the service using only thebase layer or by performing MIMO decoding and using both the base layerand the enhancement layer according to channel or receiver state.

In the above-mentioned first to third embodiments, the methods ofgenerating the base layer and the enhancement layer using SVC andtransmitting the base layer and the enhancement layer using one ofSISO/SIMO and MIMO have been described. The base layer and theenhancement layer transmitted in this manner correspond to MIMObroadcast data. A description will be given of a method of transmittingthe MIMO broadcast data including the base layer and the enhancementlayer in association with terrestrial broadcast frames for transmittingterrestrial broadcast signals. In the following description, the MIMObroadcast data including the base layer and the enhancement layer may begenerated according to one of the first to third embodiments oraccording to a combination of one or more of the first to thirdembodiments.

(1) Method of Transmitting MIMO Broadcast Data Using Predetermined PLP

It is possible to transmit the MIMO broadcast data included in apredetermined PLP while distinguishing the predetermined PLP from a PLPincluding terrestrial broadcast data. In this case, the predeterminedPLP is used to transmit the MIMO broadcast data, and signalinginformation for describing the predetermined PLP may be additionallytransmitted. In the following, the predetermined PLP including the MIMObroadcast data may be referred to as a MIMO broadcast PLP and the PLPincluding the terrestrial broadcast data may be referred to as aterrestrial broadcast PLP.

(2) Method of Transmitting MIMO Broadcast Data Using Predetermined Frame

It is possible to include the MIMO broadcast data generated as describedabove in a predetermined frame and to transmit the predetermined frameincluding the MIMO broadcast data while distinguishing the predeterminedframe from a terrestrial broadcast frame. In this case, thepredetermined frame is used to transmit the MIMO broadcast data, andsignaling information for describing the predetermined frame may beadditionally transmitted. The predetermined frame may be an FEFillustrated in FIG. 13. In the following description, the predeterminedframe including the MIMO broadcast data is referred to as a MIMObroadcast frame.

(3) Method of Transmitting MIMO Broadcast PLP Using TerrestrialBroadcast Frame and MIMO Broadcast Frame

PLPs including MIMO broadcast data may be transmitted through aterrestrial broadcast frame and a MIMO broadcast frame. Since a MIMObroadcast PLP may be present in the terrestrial broadcast frame (orbasic frame), distinguished from the above-mentioned embodiments, it isnecessary to signal the relationship between connected PLPs present inthe terrestrial broadcast frame and the MIMO broadcast frame. To achievethis, the MIMO broadcast frame may also include L1 signalinginformation, and information about the MIMO broadcast PLP present in thebroadcast frame may be transmitted along with L1 signaling informationof the terrestrial broadcast frame.

MIMO broadcast PLPs included in the MIMO broadcast frame may includeSISO, MISO and MIMO PLPs. In this case, SISO/MISO PLPs or carriers maytransmit the base layer and MIMO PLPs or carriers may transmit theenhancement layer. The proportion of the SISO/MISO PLPs or carriers andthe proportion of the MIMO PLPs may vary between 0 to 100%, and theproportions may be differently set on a per frame basis.

FIG. 21 shows structures of transmission streams transmitted by aterrestrial broadcast system to which the MIMO transmission system usingSVC according to an embodiment of the present invention is applied. FIG.21 illustrates exemplary broadcast signals using at least one of themethods described with reference to FIGS. 18 to 20 and the methods (1),(2) and (3).

FIG. 21(A) illustrates a broadcast signal including terrestrialbroadcast frames and MIMO broadcast frames. In FIG. 21(A), MIMObroadcast PLPs may be present in the terrestrial broadcast frames andMIMO broadcast frames. MIMO broadcast PLPs included in the terrestrialbroadcast frames are base layers and MIMO broadcast PLPs included in theMIMO broadcast frames are enhancement layers. The MIMO broadcast PLPsmay be transmitted according to SISO, MISO or MIMO.

FIG. 21(B) illustrates a broadcast signal including terrestrialbroadcast frames and MIMO broadcast frames. In FIG. 21(B), MIMObroadcast PLPs may be present in only MIMO broadcast frames. In thiscase, the MIMO broadcast PLPs may include a PLP including a base layerand a PLP including an enhancement layer.

FIG. 21(C) illustrates a broadcast signal including terrestrialbroadcast frames and MIMO broadcast frames. MIMO broadcast data ispresent in only MIMO broadcast frames. However, a base layer and anenhancement layer may be distinguished from each other by carriersinstead of PLPs and transmitted, distinguished from FIG. 21(C). That is,it is possible to respectively allocate data corresponding to the baselayer and data corresponding to the enhancement layer to separatesubcarriers, modulate the data according to OFDM, and transmit themodulated data, as described with reference to FIG. 19.

In the aforementioned MIMO broadcast system using SVC, the broadcastsignal transmitter may receive and process a base layer and anenhancement layer while distinguishing the base layer and theenhancement layer from each other using PLPs. For example, in the modeadaptation block 102100 for processing a plurality of PLPs, shown inFIG. 2(B), the base layer can be included in PLP0 and the enhancementlayer can be included in PLP1. The broadcast signal receivercorresponding to the broadcast signal transmitter may receive andprocess a broadcast signal including the base layer and the enhancementlayer distinguished from each other by PLPs and transmitted from thebroadcast signal transmitter. The broadcast signal transmitter maytransmit the base layer and the enhancement layer using one PLP. In thiscase, the broadcast signal transmitter may include an SVC encoder forSVC-encoding data and outputting the data as a base layer and anenhancement layer. The broadcast signal receiver corresponding to thebroadcast signal transmitter may receive and process a broadcast signalincluding a base layer and an enhancement layer transmitted through onePLP.

MIMO is a broadcast system that provides transmit/receive diversity andhigh transmission efficiency using a plurality of transmit antennas anda plurality of receive antennas. MIMO can process signals differently intemporal and spatial dimensions and transmit a plurality of data streamsthrough parallel paths simultaneously operating in the same frequencyband to achieve diversity and high transmission efficiency.

In an embodiment, MIMO can use spatial multiplexing (SM) and Golden code(GC) schemes.

A modulation scheme in broadcast signal transmission may be representedas M-QAM (Quadrature Amplitude Modulation) in the following description.That is, BPSK (Binary Phase Shift Keying) can be represented by 2-QAMwhen M is 2 and QPSK (Quadrature Phase Shift Keying) can be representedby 4-QAM when M is 4. M can indicate the number of symbols used formodulation. A description will be given of a case in which a MIMO systemtransmits two broadcast signals using two transmit antennas and receivestwo broadcast signals using two receive antennas as an example.

FIG. 22 illustrates MIMO transmission and reception systems according toan embodiment of the present invention.

As shown in FIG. 22, the MIMO transmission system includes an inputsignal generator 201010, a MIMO encoder 201020, a first transmit antenna201030, and a second transmit antenna 201040. In the following, theinput signal generator 201010 may be referred to as a divider and theMIMO encoder 201020 may be referred to as a MIMO processor.

The MIMO reception system may include a first receive antenna 201050, asecond receive antenna 201060, a MIMO decoder 201070, and an outputsignal generator 201080. In the following, the output signal generator201080 may be referred to as a merger and the MIMO decoder 101070 may bereferred to as an ML detector.

In the MIMO transmission system, the input signal generator 201010generates a plurality of input signals for transmission through aplurality of antennas. In the following, the input signal generator201010 may be referred to as a divider. Specifically, the input signalgenerator 201010 may divide an input signal for transmission into 2input signals and output the first input signal S1 and the second inputsignal S2 for MIMO transmission.

The MIMO encoder 201020 may perform MIMO encoding on the plurality ofinput signals S1 and S2 and output a first transmission signal St1 and asecond transmission signal St2 for MIMO transmission and the outputtransmission signals may be transmitted through a first antenna 201030and a second antenna 201040 via required signal processing andmodulation procedures. The MIMO encoding 201020 may perform encoding ona per symbol basis. The SM scheme or the GC scheme may be used as theMIMO encoding method. In the following, the MIMO encoder may be referredto as a MIMO processor. Specifically, the MIMO encoder may process aplurality of input signals according to a MIMO matrix and a parametervalue of the MIMO matrix which are described below.

The input signal generator 201010 is an element that outputs a pluralityof input signals for MIMO encoding and may also be an element such as ademultiplexer or a frame builder depending on the transmission system.The input signal generator 201010 may also be included in the MIMOencoder 201020 such that the MIMO encoder 201020 generates a pluralityof input signals and performs encoding on the plurality of inputsignals. The MIMO encoder 201020 may be a device that performs MIMOencoding or MIMO processing on a plurality of signals and outputs theencoded or processed signals so as to acquire diversity gain andmultiplexing gain of the transmission system.

Since signal processing should be performed on a plurality of inputsignals after the input signal generator 201010, a plurality of devicesmay be provided next to the input signal generator 201010 to processsignals in parallel or one device including one memory may be providedto sequentially process signals or to simultaneously process signals inparallel.

The MIMO reception system receives a first reception signal Sr1 and asecond reception signal Sr2 using a first receive antenna 201050 and asecond receive antenna 201060. The MIMO decoder 201070 then processesthe first reception signal and the second reception signal and outputs afirst output signal and a second output signal. The MIMO decoder 201070processes the first reception signal and the second reception signalaccording to the MIMO encoding method used by the MIMO encoder 201020.As an ML detector, the MIMO decoder 201070 outputs a first output signaland a second output signal using information regarding the channelenvironment, reception signals, and the MIMO matrix used by the MIMOencoder in the transmission system. In an embodiment, when ML detectionis performed, the first output signal and the second output signal mayinclude probability information of bits rather than bit values and mayalso be converted into bit values through FEC decoding.

The MIMO decoder of the MIMO reception system processes the firstreception signal and the second reception signal according to the QAMtype of the first input signal and the second input signal processed inthe MIMO transmission system. Since the first reception signal and thesecond reception signal received by the MIMO reception system aresignals that have been transmitted after being generated by performingMIMO encoding on the first input signal and the second input signal ofthe same QAM type or different QAM types, the MIMO reception system maydetermine a combination of QAM types of the reception signals to performMIMO decoding on the reception signals. Accordingly, the MIMOtransmission system may transmit information identifying the QAM type ofeach transmission signal in the transmission signal and the QAM typeidentification information may be included in a preamble portion of thetransmission signal. The MIMO reception system may determine thecombination of the QAM types of the reception signals from the QAM typeidentification information of the transmission signals and perform MIMOdecoding on the reception signals based on the determination.

The following is a description of a MIMO encoder and a MIMO encodingmethod that have low system complexity, high data transmissionefficiency, and high signal reconstruction (or restoration) performancein various channel environments according to an embodiment of thepresent invention.

The SM scheme is a method in which data is simultaneously transmittedthrough a plurality of antennas without MIMO encoding. In this case, thereceiver can acquire information from data that is simultaneouslyreceived through a plurality of receive antennas. The SM scheme has anadvantage in that the complexity of a Maximum Likelihood (ML) decoderthat the receiver uses to perform signal reconstruction (or restoration)is relatively low since the decoder only needs to check a combination ofreceived signals. However, the SM scheme has a disadvantage in thattransmit diversity cannot be achieved at the transmitting side. In thecase of the SM scheme, the MIMO encoder bypasses a plurality of inputsignals. In the following, such a bypass process may be referred to asMIMO encoding.

The GC scheme is a method in which data is transmitted through aplurality of antennas after the data is encoded according to apredetermined rule (for example, according to an encoding method usinggolden code). When the number of the antennas is 2, transmit diversityis acquired at the transmitting side since encoding is performed using a2×2 matrix. However, there is a disadvantage in that the complexity ofthe ML decoder of the receiver is high since the ML decoder needs tocheck 4 signal combinations.

The GC scheme has an advantage in that it is possible to perform morerobust communication than using the SM scheme since transmit diversityis achieved. However, such a comparison has been made when only the GCscheme and the SM scheme are used for data processing for datatransmission and, if data is transmitted using additional data coding(which may also be referred to as outer coding), transmit diversity ofthe GC scheme may fail to yield additional gain. This failure easilyoccurs especially when such outer coding has a large minimum Hammingdistance. For example, the transmit diversity of the GC scheme may failto yield additional gain compared to the SM scheme when data istransmitted after being encoded by adding redundancy for errorcorrection using a Low Density Parity Check (LDPC) code having a largeminimum Hamming distance. In this case, it may be advantageous for thebroadcast system to use the SM scheme having low complexity.

Accordingly, the present invention suggests that a more efficient MIMObroadcast system be designed using a robust outer code while using an SMscheme having low complexity. However, the SM scheme may have a problemassociated with reception signal reconstruction (or restoration)depending on the degree of correlation between a plurality of MIMOtransmission and reception channels.

FIG. 23 illustrates a data transmission and reception method accordingto MIMO transmission of the SM scheme in a channel environment accordingto an embodiment of the present invention.

The MIMO transmission system may transmit input signal 1 (S1) and inputsignal 2 (S2) respectively through transmit antenna 1 and transmitantenna 2 according to the SM scheme. FIG. 23 illustrates an embodimentin which the transmitting side transmits a symbol modulated according to4-QAM.

The transmit antenna 1 receives a signal through two paths. In thechannel environment of FIG. 23, the received signal of the receiveantenna 1 is S1*h₁₁+S2h₂₁ and the received signal of the receive antenna2 is S1*h₁₂+S2h₂₂. The receiving side may acquire S1 and S2 throughchannel estimation to reconstruct data.

This is a scenario in which the transmission and reception paths areindependent of each other. In the following, such an environment isreferred to as being uncorrelated. On the other hand, channels of thetransmission and reception paths may have a very high correlation witheach other as in a Line Of Sight (LOS) environment, which is referred toas being fully correlated in the following description.

In the case in which channels are fully correlated in MIMO, each channelmay be represented by a 2×2 matrix whose elements are all 1 (i.e.,h₁₁=h₁₂=h₂₁=h₂₂=1) as shown in FIG. 23. Here, the receive antenna 1 andthe receive antenna 2 receive the same reception signal (S1+S2). Thatis, if signals transmitted through 2 transmit antennas pass through thesame channel and are received by 2 receive antennas, a reception signalreceived by the receiver, i.e., data added (or combined) through thechannel, cannot express both symbols S1 and S2. As shown in FIG. 23, inthe fully correlated channel environment, the receiver cannot receive a16-QAM symbol, into which the signal S1 represented by a 4-QAM symboland the signal S2 represented by a 4-QAM symbol are combined and thereceiver cannot separate and reconstruct the signals S1 and S2 since thereceiver receives a combined signal S1+S2 represented by 9 symbols asshown on the right side of FIG. 23.

In the following, a received signal that has passed through fullycorrelated channels may be represented by a signal corresponding to thesum of signals transmitted by the transmission system. That is, the MIMOencoding method will now be described on the assumption that, when thetransmission system having two antennas transmits a first transmissionsignal and a second transmission signal, a received signal that haspassed through the fully correlated channels corresponds to the sum ofthe first and second transmission signals.

In this case, the receiver cannot reconstruct a signal receivedaccording to MIMO using the SM scheme even when the receiver is in avery high SNR environment. In the case of a communication system,communication is generally performed in two ways and therefore such achannel environment may be signaled to the transmitter through afeedback channel established between the transmitter and the receiver toallow the transmitter to change the transmission method. However, in thecase of a broadcast system, it may be difficult to perform bidirectionalcommunication through a feedback channel and one transmitter covers alarge number of receivers and a large range and therefore it may bedifficult to deal with various channel environment changes. Accordingly,if the SM scheme is used in such a fully correlated channel environment,the receiver cannot receive services and it is difficult to deal withsuch an environment, increasing costs, unless the coverage of thebroadcast network is reduced.

The following is a description of a method for dealing with the case inwhich the correlation between MIMO channels is 1, i.e., the case inwhich channels are in a fully correlated channel environment.

The present invention suggests that a MIMO system be designed such thatsignals received through MIMO channels satisfy the following conditionsso as to deal with the case in which the MIMO channels are fullycorrelated.

1) A received signal should be able to represent both original signalsS1 and S2. That is, coordinates of a constellation received by thereceiver should be able to uniquely represent sequences of S1 and S2.

2) A minimum Euclidean distance of a received signal should be increasedso as to reduce symbol error rate.

3) Hamming distance characteristics of a received signal should be goodso as to reduce bit error rate.

First, the present invention suggests a MIMO encoding method that uses aMIMO encoding matrix including an encoding factor “a” as expressed inthe following Equation 1 so as to satisfy such requirements.

$\begin{matrix}\begin{bmatrix}1 & a \\a & {- 1}\end{bmatrix} & \left\lbrack {{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$

When a MIMO encoder encodes input signals S1 and S2 using a MIMOencoding matrix as shown in Equation 1, reception signal 1 (Rx1) andreception signal 2 (Rx2) received by antenna 1 and antenna 2 arecalculated as expressed in the following Equation 2. The receptionsignal 1 (Rx1) and reception signal 2 (Rx2) are calculated as expressedin the last line of Equation 2, especially, when MIMO channels are fullycorrelated.

Rx ₁ =h ₁₁(S1+aS2)+h ₂₁(aS1−S2)

Rx ₂ =h ₁₂(S1+aS2)+h ₂₂(aS1−S2)

R=Rx ₁ =Rx ₂ =h{(a+1)S1+(a−1)S2}, if h ₁₁ =h ₂₁ =h ₁₂ =h ₂₂=h,  [Equation 2]

First, when MIMO channels are uncorrelated, the reception signal 1 (Rx1)is calculated as Rx1=h₁₁(S1+a*S2)+h₂₁(a*S1−S1) and the reception signal2 (Rx2) is calculated as Rx2=h₁₂(S1+a*S2)+h₂₂(a*S1-S2). Thus, since thesignals S1 and S2 have the same power, it is possible to use gain of theMIMO system together with the SM scheme. When MIMO channels are fullycorrelated, the reception signals (R=Rx1=Rx2) expressed asR=h{(a+1)S1+(a−1)S2} are acquired and therefore it is possible toseparate and acquire the signals S1 and S2 and the signals S1 and S2 aredesigned such that both have different power and therefore it ispossible to secure robustness accordingly.

That is, the MIMO encoder may encode input signals S1 and S2 such thatthe input signals S1 and S2 have different powers according to theencoding factor “a” and are also received with different distributionseven in fully correlated channels. For example, input signals S1 and S2may be encoded such that both have different powers and the encodedsignals may then be transmitted using constellations which havedifferent Euclidean distances through normalization to allow thereceiver to separate and reconstruct the input signals even when thesignals have passed through fully correlated channels.

The MIMO encoding matrix described above may be represented as Equation3 taking into consideration a normalization factor.

$\begin{matrix}\begin{matrix}{{\frac{1}{\sqrt{1 + a^{2}}}\begin{pmatrix}1 & a \\a & {- 1}\end{pmatrix}} = \begin{pmatrix}\frac{1}{\sqrt{1 + a^{2}}} & \frac{a}{\sqrt{1 + a^{2}}} \\\frac{a}{\sqrt{1 + a^{2}}} & \frac{- 1}{\sqrt{1 + a^{2}}}\end{pmatrix}} \\{= \begin{bmatrix}{\cos \; \theta} & {\sin \; \theta} \\{\sin \; \theta} & {{- \cos}\; \theta}\end{bmatrix}}\end{matrix} & \left\lbrack {{Equation}\mspace{14mu} 3} \right\rbrack\end{matrix}$

MIMO encoding of the MIMO encoder that uses the MIMO encoding matrix (orrotation matrix) shown in Equation 3 may be considered as rotating theinput signals by an arbitrary angle of θ that can be represented by theencoding factor a, separating the cosine and sine components (or realand imaginary components) of the rotated signals, assigning positive andnegative (+/−) signs to the separated components, and transmitting theseparated components through different antennas. For example, the MIMOencoder may encode the input signals S1 and S2 such that the cosinecomponent of the input signal S1 and the sine component of the inputsignal S2 are transmitted through one transmit antenna and the sinecomponent of the input signal S1 and the cosine component of the inputsignal S2 to which a negative sign is attached are transmitted throughanother transmit antenna. The angle, by which the input signals arerotated, changes according to change of the value of the encoding factor“a” and the power distributions of the input signals S1 and S2 becomedifferent according to the value of the factor and the angle. Since thepower distribution difference can be represented by a distance betweensymbol coordinates in the constellations, the encoded input signals canbe represented by different constellations even when the input signalsare received by the receiving side via fully correlated channels suchthat it is possible to identify and separate the signals, therebyenabling reconstruction of the original input signals.

Specifically, the Euclidian distances of transmission signals change asthe power distributions change, the transmission signals received by thereceiving side can be represented by identifiable constellations havingdifferent Euclidian distances such that it is possible to reconstructthe signals even when the signals have passed through a fully correlatedchannel. That is, the MIMO encoder can encode the input signal S1 andthe input signal S2 into signals having different Euclidian distancesaccording to the value “a” and the receiving side can receive andreconstruct the encoded and transmitted signals using identifiableconstellations.

MIMO encoding of the input signals using the above-described MIMOencoding matrix may be represented as Equation 4.

$\begin{matrix}{\begin{pmatrix}{X\; 1} \\{X\; 2}\end{pmatrix} = {\frac{1}{\sqrt{1 + a^{2}}}\begin{pmatrix}1 & a \\a & {- 1}\end{pmatrix}\begin{pmatrix}{S\; 1} \\{S\; 2}\end{pmatrix}}} & \left\lbrack {{Equation}\mspace{14mu} 4} \right\rbrack\end{matrix}$

In Equation 4, S1 and S2 respectively represent normalized QAM symbolsof constellations mapped by symbol mappers on MIMO paths of the inputsignals S1 and S2. X1 and X2 respectively denote MIMO-encoded symbols.That is, the MIMO encoder can apply the matrix as represented byEquation 4 to the first input signal including the symbols correspondingto S1 and the second input signal including the symbols corresponding toS2 to output a first transmission signal including the symbolscorresponding to X1 and a second transmission signal including thesymbols corresponding to X2.

The MIMO encoder may perform encoding on input signals using the MIMOencoding matrix described above while additionally adjusting theencoding factor a. That is, it is possible to adjust and optimize theencoding factor “a” taking into consideration additional datareconstruction performance of the MIMO transmission and receptionsystem.

1. First Embodiment MIMO Encoding Method that Optimizes the EncodingFactor “a” Taking into Consideration Euclidian Distances (in a FullyCorrelated MIMO Channel Environment).

It is possible to calculate the encoding factor value “a” taking intoconsideration the Euclidean distance while using the MIMO encodingmatrix. In a MIMO system having two transmit antennas and two receiveantennas, when transmission signal St1 is an M-QAM symbol andtransmission signal St2 is an N-QAM symbol, a signal St1+St2 that isreceived by the receiving side via a fully correlated MIMO channel is an(M*N)-QAM signal. Additionally, in a MIMO system having 2 transmissionantennae and 2 reception antennae, when the transmission signal St1corresponds to an M-QAM symbol, and when the transmission signal St2corresponds to an M-QAM symbol, the signal St1+St2 passing through afully correlated channel and being received by the receiving end becomesan (M*M)-QAM signal.

The first embodiment of the present invention suggests a method foroptimizing the value “a” such that symbols have the same Euclidiandistance in a constellation of a symbol of a reception signal that haspassed through a fully correlated channel. That is, in the case in whichinput signals are encoded using the MIMO matrix, it is possible tocalculate or set the value of the encoding factor “a” such thatreception symbols have the same Euclidean distances in a constellationof a reception signal that has passed through a fully correlated channeland to encode the input signals using the calculated or set value “a” ofthe encoding factor. Such a value “a” may be represented by Equation 5for each modulation scheme combination.

$\begin{matrix}{a = \left\{ \begin{matrix}{3,} & {{{for}\mspace{14mu} {QPSK}} + {QPSK}} \\{{\left( {4 + \sqrt{5}} \right)/\left( {4 - \sqrt{5}} \right)},} & {{{for}\mspace{14mu} {QPSK}} + {16\; {QAM}}} \\{0.6,} & {{{for}\mspace{14mu} 16\; {QAM}} + {16\; {QAM}}}\end{matrix} \right.} & \left\lbrack {{Equation}\mspace{14mu} 5} \right\rbrack\end{matrix}$

The distribution and constellation of the transmission and receptionsymbols change according to modulation schemes of the reception signalsand a combination of the modulation schemes and the Euclidean distancechanges according to the distribution and constellation of the symbolsand therefore the value “a” for optimizing the Euclidean distance mayalso change accordingly. Equation 3 also shows an encoding factor value“a” for optimizing the Euclidean distance calculated when transmissionand reception signals are a combination of 4-QAM and 16-QAM (i.e.,QPSK+16-QAM) and an encoding factor value “a” calculated whentransmission and reception signals are a combination of 16-QAM and16-QAM (i.e., 16-QAM+16-QAM).

In other words, in the first embodiment, the value “a” is set such thatthe constellation of a signal obtained by summing first and secondtransmission signals that are obtained by MIMO-encoding first and second4-QAM input signals, for example, is identical to the constellation of a16-QAM signal.

2. Second Embodiment MIMO Encoding Method Taking into Consideration GrayMapping in Addition to Euclidian Distance

The second embodiment suggests a MIMO encoding method in which anencoding factor value “a” is set so as to optimize the Euclideandistance, similar to the first embodiment, and MIMO encoding isperformed such that a reception signal that has passed through a fullycorrelated channel has a gray mapping (or gray mapping form).

In the MIMO encoding method of the second embodiment, at the receivingside, the signs of real and imaginary parts of the input signal S2 amongthe input signals S1 and S2 may be changed according to a value of theinput signal S1 such that each signal becomes a gray mapping signal.Data values included in the input signal S2 may be changed using amethod represented by the following Equation 6.

That is, the MIMO encoder may perform MIMO encoding after changing signsof the input signal S2 according to the value of the input signal S1while using the same MIMO encoding factor as used in the firstembodiment. In other words, the sign of the input signal S2 may bedetermined according to the sign of the input signal S1, and then theMIMO encoding matrix may be applied to the first and second inputsignals S1 and S2 to output the first and second transmission signals,as described above.

S1=b ₀ b ₁ . . . b _(N-) , N=log ₂ M, M=QAM size of S1

real(S1)=b ₀ b ₂ . . . b _(N-2)

imag(S1)=b ₁ b ₃ . . . b _(N-1)

for i=1 . . . N−1

si=sq=1

if i=index of real(S1) and b _(i)=1

si=−si

if i=index of imag(S1) and b _(i)=1

sq=−sq

end for

S2=si·real(S2)+i·sq·imag(S2)  [Equation 6]

If bit values assigned to the real and imaginary parts of the inputsignal S1 among the input signals S1 and S2 and are XORed as in Equation6 and the signs of the real and imaginary parts are determined accordingto the XORed value and transmission signal 1 and transmission signal 2are transmitted respectively through antenna 1 and antenna 2, thenreception symbols of a reception signal, which is received by thereceiver via a fully correlated channel, have a gray mapping form suchthat the Hamming distance between adjacent symbols in the constellationdoes not exceed 2.

Since an (M*N)-QAM signal received by the receiver has a minimumEuclidean distance and a gray mapping form, the second embodiment mayachieve the same performance as the SIMO scheme even in a fullycorrelated MIMO channel environment. However, when signals S1 and S2 areacquired by decoding the reception signal at the ML decoder, complexitymay be increased since the value of S2 depends on the value of S1 andperformance may be degraded due to the correlation between input signalsin an uncorrelated MIMO channel.

3. Third Embodiment MIMO Encoding Method that Sets MIMO Encoding FactorTaking into Consideration Hamming Distance in Addition to EuclidianDistance

The third embodiment suggests a method in which MIMO encoding isperformed by setting an encoding factor value “a” so as to optimize theEuclidian distance taking into consideration the Hamming distance of areception signal rather than allowing the entire constellation of thereception signal to have a Euclidian distance as in the firstembodiment.

In the third embodiment, the Euclidian distance is adjusted so as tocompensate for the reconstruction performance difference due to theHamming distance difference using the power difference. That is, theEuclidian distance between adjacent symbols in an interval, whoseHamming distance is twice greater than another interval since the numberof bits thereof is twice greater than the other interval, can beincreased so as to increase power of the interval, thereby compensatingfor performance degradation due to the Hamming distance difference whena reception signal is reconstructed. First, a relative Euclidiandistance of a reception signal into which 2 transmission signals St1 andSt2 received by the receiver are combined is determined. It can be seenfrom the above Equation 1 that the minimum Euclidean distance of a16-QAM symbol whose power is reduced is 2(a−1) and the minimum Euclideandistance of a 16-QAM symbol whose power is increased is 2(a+1) (sinceone reception signal is expressed as R=h{(a+1)S1+(a−1)S2}). This may berepresented by Equation 7.

$ \begin{matrix}{{{2\; D_{H_{1}}} = D_{H_{2}}}{{\sqrt{2\;}D_{E_{1}}} = D_{E_{2}}}{{2\sqrt{2}\left( {a - 1} \right)} = {2\left( {\left( {a + 1} \right) - {3\left( {a - 1} \right)}} \right)}}{a = \frac{\sqrt{2} + 4}{\sqrt{2} + 2}}} & \left\lbrack {{Equation}\mspace{14mu} 7} \right\rbrack\end{matrix}$

That is, the MIMO encoder performs MIMO encoding on input signals bydistributing different powers to the input signals using the MIMO matrixsuch that the signals have different Euclidian distances. In this case,the MIMO encoder may perform MIMO encoding by calculating and settingthe encoding factor value “a” such that input signals with distributedpower have Euclidian distances for compensating for a Hamming distancedifference according to the third embodiment.

A description will be given of an MIMO transmitter and MIMO receiverusing the aforementioned MIMO method.

FIG. 24 is a block diagram illustrating a MIMO transmitter and a MIMOreceiver according to an embodiment of the present invention.

FIG. 24 illustrates an embodiment in which the MIMO transmitter and theMIMO receiver perform MIMO communication using two antennas,respectively. Particularly, the MIMO transmitter uses the samemodulation scheme for input signals. That is, M-QAM is used as amodulation scheme for two input signals to transmit the two inputsignals through two antennas (e.g. QPSK+QPSK or 16-QAM+16-QAM).Hereinafter, this may be expressed as an M-QAM+M-QAM.

The MIMO transmitter may include a BICM module 209010, a frame builder209020, a frequency interleaver 209030, a MIMO encoder 209040, and anOFDM generator 209050. The BICM module 209010 may include an FEC encoder209060, a bit interleaver 209070, a demultiplexer 209080, a symbolmapper 209090, and a time interleaver 209100. The MIMO encoder 209040may be referred to as a MIMO processor.

The MIMO receiver may include an OFDM demodulator 209110, a MIMO decoder209120, a frequency deinterleaver 209130, a frame parser 209140, a timedeinterleaver 209150, a multiplexer 209160, a bit deinterleaver 209170,and an FEC decoder 209180. The time deinterleaver 209150, themultiplexer 209160, the bit deinterleaver 209170 and the FEC decoderperform a reverse procedure of the procedure of the BICM module and maybe referred to as a BICM decoding module 209190 in the following. TheMIMO decoder 209120 may be referred to as a MIMO maximum likelihood (ML)detector.

Hereinafter, the elements of the MIMO transmitter may perform the samefunctions as the blocks included in the broadcast signal transmittershown in FIG. 1 to FIG. 6, and the elements of the MIMO receiver mayperform the same functions as the blocks included in the broadcastsignal receiver shown in FIG. 7 to FIG. 11. Therefore, detaileddescription of the same or similar functions will be omitted forsimplicity.

In the MIMO transmitter, a plurality of PLPs is input to respective BICMpaths. FIG. 24 illustrates that one PLP is input to the BICM module209010. The MIMO transmitter may include a plurality of BICM modules andPLPs respectively subjected to BICM may be applied to the frame builder209020. The demultiplexer 209080 demultiplexes the bitstreams on thebasis of M-QAM. The symbol mapper 209090 performs M-QAM gray mapping onthe bitstreams output from the demultiplexer 209080 to output M-QAMsymbol streams. The time interleaver 209100 interleaves the symbolstreams in time and, particularly, time-interleaves symbols output fromone or more LDPC blocks. In FIG. 24, signal processing in blocksfollowing the symbol mapper may be performed on a symbol-by-symbolbasis.

The frame builder 209020 arranges the symbols in PLPs, output througheach BICM path, in frames. The frame builder 209020 additionallyfunctions as an input signal generator that generates or arranges aplurality of input signals for MIMO transmission. Here, the framebuilder 209020 in the MIMO transmitter may arrange symbols such thatdifferent PLPs are not encoded together. In the embodiment of FIG. 24 inwhich signals are transmitted using two antennas, the frame builder209020 may arrange two different symbols in the same cell position togenerate and output two input signals. When the frame builder 209020outputs two symbol data (i.e. two input signals) allocated to the samecell position in parallel, the frequency interleaver 209030 interleavesthe two symbol data in the same pattern in the frequency domain. TheMIMO encoder 209040 MIMO-encodes the two input signals for the twoantennas, that is, the two symbol data output from the frequencyinterleaver 209030. Here, the MIMO encoding method can be used for MIMOencoding, and thus the aforementioned MIMO encoding matrix includingparameter a can be used.

The OFDM generator 209050 may OFDM-modulate the MIMO-encoded symbol dataand transmit the OFDM-modulated symbol data. The MIMO encoder 209040 mayperform MISO processing or SISO processing in addition to MIMO encoding.In the embodiment of FIG. 24, the MIMO transmitter may use two antennaswhen only MIMO processing is performed and may use four antennas whenMISO processing is additionally performed. When all PLPs are processedaccording to SISO and transmitted, one to four antennas may bearbitrarily used.

The MIMO receiver uses at least two antennas to receive a MIMO signal.If a received signal is a SISO signal or a MISO signal, the MIMOreceiver may use one or more antennas.

The MIMO transmitter may include as many frequency interleavers and OFDMgenerators as the number of input signals transmitted to a plurality ofantennas, which are arranged in parallel, such that the frequencyinterleavers 209030 and the OFDM generator 209050 can perform theaforementioned operations in parallel. Otherwise, one frequencyinterleaver 209030 and one OFDM generator 209050 may include memories toprocess a plurality of signals in parallel.

In the MIMO receiver, the OFDM demodulator 209110 OFDM demodulates aplurality of receiving signals that are received from a plurality ofantennae and transmits a plurality of symbol data and channelinformation.

The MIMO decoder 209120 processes the channel information and theplurality of received symbol data output from the OFDM demodulator209110 and outputs a plurality of output signals. The MIMO decoder209120 can use the following Equation 8.

$\begin{matrix}{\log \left( \frac{\sum\limits_{s \in S_{0}}^{{- \frac{1}{2\; \sigma^{2}}}{\sum\limits_{s,h,t}{{y_{h,t} - {H_{h,t}{WS}_{s}}}}^{2}}}}{\sum\limits_{s \in S_{1}}^{{- \frac{1}{2\; \sigma^{2}}}{\sum\limits_{s,h,t}{{y_{h,t} - {H_{h,t}{WS}_{s}}}}^{2}}}} \right)} & \left\lbrack {{Equation}\mspace{14mu} 8} \right\rbrack\end{matrix}$

In Equation 8, y_(h,t), denotes a signal received by the receiver whereh denotes a channel received for each receive antenna. That is, y_(h,t)represents a received signal that has passed through a channelcorresponding to time t. For example, y_(h,t) represents signalsreceived during one unit time and represents signals received for timeof two units in the case of the GC scheme. H_(h,t) denotes channelinformation to which the received signal has been subjected. In theembodiments of the present invention, h may be represented by a 2×2matrix indicating a MIMO channel and t denotes a time unit. W denotes aMIMO encoding matrix and S_(s) is a transmitted QAM signal thatrepresents an input signal before MIMO-encoding. In addition, s is aunit for two signals used for MIMO transmission.

In Equation 8, ∥Y−HWS∥² represents a difference between a receivedsignal vector (two signals can be referred to as a vector because theyare simultaneously transmitted) and a transmitited signal vector, andthe receiver detects vector S_(s) that minimize the difference. Sincethe receiver knows y_(h,t), H_(h,t) and W, the receiver can acquire alog likelihood ratio (LLR) by comparing probability S1 that acorresponding bit is 1 with probability S0 that the corresponding bit is0 in the log domain.

As described above, the MIMO decoder 209120 uses a method of detecting asignal closest to a transmitted signal from a received signal usingEquation 8, and information acquired from the detection is bit-basedprobability, and thus a plurality of output signals of the MIMO decoder209120 bit-based data represented in an LLR. Here, the MIMO decoder209120 compares all combinations of data used for MIMO encoding andchannel information with received data in order to obtain the LLR. Inthis case, the MIMO decoder 209120 may use an approximated ML schemethat uses only a value closest to the received data, a sphere decodingscheme that uses only a combination of values within a predetermineddistance from the received data, etc. That is, in FIG. 24, the MIMOdecoder 209120 MIMO-decodes two signals received through the twoantennas to output as many output signals S1 and S2 as the number ofinput signals of the transmitter. Here, the output signals S1 and S2 maybe bitstreams. In this case, the output signals correspond to QAM typesof the input signals of the transmitter.

In the expression used for decoding of the MIMO decoding, WS and W areMIMO encoding matrices and include all MIMO matrices of theaforementioned MIMO encoding methods. The transmitter may transmitinformation about a MIMO matrix used therein and the receiver may checkthe MIMO matrix using the information and perform decoding. Optionally,the receiver may use a predetermined MIMO matrix.

The frequency deinterleaver 209130 performs deinterleaving on theplurality of output signals of the MIMO decoder 209120 in order reverseto the interleaving operation of the frequency interleaver 209030 of thetransmitter. While the frequency interleaver 209030 of the transmitterperforms frequency interleaving on a symbol-by-symbol basis, thefrequency deinterleaver 209130 of the receiver reorders LLR bitinformation included in one QAM symbol as symbols and outputs thesymbols because it uses LLR bit information. The MIMO receiver mayinclude a plurality of frequency deinterleavers to respectively performfrequency deinterleaving on MIMO input signals in parallel.

The frame parser 209140 acquires desired PLP data from the data outputfrom the frequency deinterleaver 209130 and output the acquired PLPdata. The time deinterleaver 209150 performs deinterleaving in reverseorder to the interleaving operation of the time interleaver 209100 ofthe transmitter. Here, the time deinterleaver 209150 performsdeinterleaving on a bit-by-bit basis, distinguished from thetransmitter, and thus it reorders bitstreams in consideration of LLR bitinformation and outputs the reordered bitstreams. The frame parser209140 reorders a plurality of signals input thereto into one stream byperforming frame parsing on the input signals and outputs the stream.That is, the frame parser 209140 performs the operation of the outputsignal generator illustrated in FIG. 22, and blocks following the frameparser 209140 in the receiver carry out signal processing on one stream.

The multiplexer 209160, the bit deinterleaver 209170 and the FEC decoder209180 respectively perform operations reverse to the operations of thedemultiplexer 209080, the bit interleaver 209070 and the FEC encoder209060 of the transmitter, to output restored PLPs. That is, themultiplexer 209160 realigns the LLR bit information, the bitdeinterleaver 209170 performs bit deinterleaving, and the FEC decoder209180 performs LDPC/BCH decoding to correct errors and output PLP bitdata. Operations following the operation of the frame parser may beregarded as BICM decoding operation of the BICM decoding module, whichis reverse to the operation of the BICM module 209010 of thetransmitter.

The MIMO transmitter and the MIMO receiver may include as many frequencyinterleavers 209030, frequency deinterleavers 209130, OFDM generators209050 and OFDM demodulators 209110 as the number of MIMOtransmitted/received signals so as to perform the aforementionedoperations on the MIMO transmitted/received signals in parallel.Otherwise, the frequency interleaver 209030, frequency deinterleaver209130, OFDM generator 209050 and OFDM demodulator 209110 may includememories that simultaneously process a plurality of data signals toreduce system complexity.

FIG. 25 illustrates a MIMO transmitter and a MIMO receiver according toanother embodiment of the present invention.

FIG. 25 shows a case in which each of the MIMO transmitter and the MIMOreceiver uses two antennas to perform MIMO communication. Particularly,in the MIMO transmitter, it is assumed that the same modulation schemeis used for input signals. That is, two input signals to be transmittedusing the two antennas are modulated through M-QAM (e.g. QPSK+QPSK,16-QAM+16-QAM). Hereinafter, this may be expressed as M-QAM+M-QAM.

The MIMO transmitter includes a BICM module 210010, a frame builder210020, a frequency interleaver 210030, and an OFDM generator 210040.The BICM module 210010 includes an FEC encoder 210050, a bit interleaver210060, a demultiplexer 210070, a symbol mapper 210080, a MIMO encoder210090 and a time interleaver 210100.

The MIMO receiver includes an OFDM demodulator 210110, a frequencydeinterleaver 210120, a frame parser 210130, a time deinterleaver210140, a MIMO ML detector 210050, a multiplexer 210160, a bitdeinterleaver 210170, and an FEC decoder 210170. The time deinterleaver210150, multiplexer 210160, bit deinterleaver 210170 and FEC decoder210170 perform an operation reverse to the operation of the BICM module210010 of the MIMO transmitter and may be referred to as a BICM decodingmodule 210190 in the following description.

Configurations and operations of the MIMO transmitter and MIMO receiverof FIG. 25 are similar to those of the MIMO transmitter and MIMOreceiver of FIG. 24, and thus only a difference therebetween will bedescribed now.

The MIMO encoder 210090 of the MIMO transmitter of FIG. 25 is locatedbetween the symbol mapper 210080 and the time interleaver 210100, thatis, included in the BICM module 210010, distinguished from the MIMOencoder shown in FIG. 24. That is, the MIMO encoder 210090 receivessymbols output from the symbol mapper 210080, arranges the symbols inparallel, MIMO-encodes the symbols and outputs the MIMO-encoded symbolsin parallel, distinguished from the embodiment of FIG. 24 in which theframe builder outputs QAM symbols to be MIMO-encoded in parallel. TheMIMO encoder 210090 additionally functions as an input signal generatorto generate a plurality of input signals, perform MIMO encoding on theinput signals and output a plurality of transmission signals. The MIMOtransmission data output in parallel from the MIMO encoder 210090 areprocessed in parallel in the time interleaver 210100, frame builder210020, frequency interleaver 210030 and OFDM generator 210040 andtransmitted. Here, a plurality of time interleavers 210100, framebuilders 210020, frequency interleavers 210030 and OFDM generators210040 may be provided to process the MIMO transmission data inparallel. In the embodiment of FIG. 25 in which two transmit antennasare used, the MIMO transmitter may include two time interleavers 210100,two frame builders 210020, two frequency interleavers 210030, and twoOFDM generators 210040 to process data output from the MIMO encoder210090 in parallel.

In the MIMO receiver of FIG. 25, the MIMO decoder 210150 is locatedbetween the time deinterleaver 210140 and the multiplexer 210160.Accordingly, the OFDM demodulator 210110, frequency deinterleaver210120, frame parser 210130 and time deinterleaver 210140 process MIMOsignals received through a plurality of antennas on a symbol-by-symbolbasis on a plurality of paths, and the MIMO decoder 210150 convertssymbol-based data into LLR bit data and output the LLR bit data. In theembodiment of FIG. 25, the MIMO receiver may include a plurality of OFDMdemodulators 210110, frequency deinterleavers 210120, frame parsers210130, and time deinterleavers 210140. Alternatively, the OFDMdemodulator 210110, frequency deinterleaver 210120, frame parser 210130and time deinterleaver 210140 may include memories capable of performingthe aforementioned parallel processing. Since all the frequencydeinterleaver 210120, frame parser 210130 and time deinterleaver 210140process symbol-based data, system complexity or memory capacity can bereduced, as compared to the embodiment of FIG. 24 in which LLR bitinformation is processed.

In FIGS. 24 and 25, the MIMO transmitters may transmit informationrepresenting a combination of QAM types of the input signals, used forMIMO encoding. That is, information representing QAM types of the firstand second input signals output from the frame builder 210020 may betransmitted through a preamble. In the present embodiment, the first andsecond input signals have the same QAM type. That is, the MIMO decoderchecks the information representing the combination of the QAM types ofthe input signals included in received signals and performs MIMOdecoding using a MIMO matrix corresponding to the combination of the QAMtypes, to output signals corresponding to the combination of the QAMtypes. The output signals of the QAM types include bit-based data, andthis bit-based data are soft decision values that represent theaforementioned probability of bits. These soft decision values can beconverted into hard decision values through FEC decoding.

In FIGS. 24 and 25, devices corresponding to the input signalgenerator/output signal generator are the frame builder/frame parser andthe MIMO encoder/MIMO decoder. However, the operations of the inputsignal generator/output signal generator may be performed by otherdevice elements. For example, the demultiplexer serves as the inputsignal generator or is followed by the input signal generator in thetransmitter, and the multiplexer serves as the output signal generatoror is located behind the output signal generator in the receivercorresponding to the transmitter. Each element located behind the inputsignal generator may be provided as a plurality of elements to processoutput signals of the input signal generator in parallel along as manypaths as the number of the output signals of the input signal generator,and each element located before the output signal generator may beprovided as a plurality of elements to process input signals applied tothe output signal generator in parallel along as many paths as thenumber of the input signals of the output signal generator, according tolocations of the input signal generator/output signal generator.

FIG. 26 illustrates a MIMO transmitter and a MIMO receiver according toanother embodiment of the present invention.

FIG. 26 shows an embodiment in which each of the MIMO transmitter andthe MIMO receiver performs MIMO transmission using two antennas.Particularly, unlike FIGS. 24 and 25, different modulation schemes areused for respective input signals. That is, two input signals to betransmitted using the two antennas are modulated through M-QAM and N-QAM(e.g. BPSK+QPSK or QPSK+16-QAM). In the following, cases in whichmodulation schemes used for input signals are QPSK+QPSK, QPSK+16-QAM and16-QAM+16-QAM will be also described in association with the operationof a demultiplexer.

Configurations of the MIMO transmitter and MIMO receiver of FIG. 26 aresimilar to those of the MIMO transmitter and MIMO receiver of FIG. 24and operations thereof are distinguished by a combination of QAM typesfrom those of the MIMO transmitter and MIMO receiver of FIG. 24.Accordingly, only a difference between the operations of the MIMOtransmitter/MIMO receiver of FIG. 26 and the MIMO transmitter/MIMOreceiver of FIG. 24 will now be described.

The MIMO transmitter may include a BICM module 211010, a frame builder211020, a frequency interleaver 211030, a MIMO encoder 211040 and anOFDM generator 211050. The BICM module 211010 may include an FEC encoder211060, a bit interleaver 211070, a demuliplexer 211080, a symbol mapper211090 and a time interleaver 211100. The MIMO encoder 211040 may bereferred to as a MIMO processor.

The MIMO receiver may include an OFDM demodulator 211110, a MIMO decoder211120, a frequency deinterleaver 211130, a frame parser 211140, a timedeinterleaver 211150, a multiplexer 211160, a bit interleaver 211170,and an FEC decoder 211180. The time interleaver 211150, multiplexer211160, bit deinterleaver 211170 and FEC decoder 211180 may perform anoperation reverse to the operation of the BICM module 211010 of the MIMOtransmitter and may be referred to as a BICM decoding module 211190. TheMIMO decoder 211120 may be referred to as a MIMO ML detector.

In MIMO transmitter, multiple PLPs may be inputted to respective BICMpaths. FIG. 11 illustrates an embodiment that single PLP is beinginputted to the BICM module 211010. Herein, a plurality of BICM modulesmay be provided, and each of the separately BICM-processed PLPs may beinputted to the frame builder 211020.

The demultiplexer 211080 demultiplexes bitstreams according to M-QAM andN-QAM and outputs demultiplexed bitstreams. The demultiplexer 211080additionally functions as the input signal generator that generates orarranges a plurality of input signals for MIMO transmission, describedwith reference to FIG. 24. The symbol mapper 211090 performs M-QAM/N-QAMgray mapping on the bitstreams output from the demultiplexer 211080 tooutput an M-QAM symbol stream and an N-QAM symbol stream. Here, the MIMOtransmitter may include a plurality of symbol mappers such that thesymbol mappers perform M-QAM/N-QAM gray mapping on a bitstreamdemultiplexed according to M-QAM and a bitstream demultiplexed accordingto N-QAM in parallel to output an M-QAM symbol stream and an N-QAMsymbol stream. The time interleaver 211100 interleaves the symbolstreams in time and, particularly, time-interleaves symbols output fromone or more LDPC blocks. In FIG. 26, signal processing by blocksfollowing the symbol mapper may be performed on a symbol-by-symbolbasis.

The demultiplexer 211080 may operate differently according to QAM sizeof an input signal used for MIMO. That is, a QAM demultiplexer and a16-QAM demultiplexer may be used when a combination of input signals forMIMO transmission is QPSK+QPSK or 16-QAM+16-QAM, whereas a 64-QAMdemultiplexer may be used in the case of QPSK+16-QAM. Otherwise, a16-QAM demultiplexer and a 256-QAM demultiplexer may be used in the caseof QPSK+QPSK and 16-QAM+16-QAM. This uses the fact that M+N-QAM MIMOtransmission simultaneously transmits bits corresponding to bitstransmitted by M*N QAM SISO.

The Frame builder 211020 arranges symbols of PLP units that areoutputted through respective BICM paths in a frame.

In the MIMO receiver, the frequency deinterleaver 211130 deinterleaves aplurality of output signals from the MIMO decoder 211120 in orderreverse to the interleaving operation of the frequency interleaver211030 of the MIMO transmitter. The frequency deinterleaver 211130 mayfrequency-deinterleave MIMO input signals in parallel. Particularly,since the number of bits included in M-QAM symbol data and the number ofbits included in N-QAM symbol data in the MIMO input signals may bedifferent from each other, the frequency deinterleaver 211130 needs toperform deinterleaving in consideration of the difference between thenumber of bits included in M-QAM symbol data and the number of bitsincluded in N-QAM symbol data. The frame parser 211140 and the timedeinterleaver 211150, which will be described below, also needs toconsider the difference between the number of bits included in M-QAMsymbol data and the number of bits included in N-QAM symbol data.

The frame parser 211140 acquires desired PLP data from output data ofthe frequency deinterleaver 211130 and outputs the acquired PLP data,and the time deinterleaver 211150 performs deinterleaving in orderreverse to the operation of the time interleaver 211100 of the MIMOtransmitter. The frame parser 211140 performs frame parsing on aplurality of input signals to reorder the plurality of input signals andoutputs the reordered signals. The multiplexer 46160, bit deinterleaver46170 and FEC decoder 46180 respectively perform operations reverse tooperations of the demultiplexer 46080, bit interleaver 46070 and FECencoder 46060 of the MIMO transmitter to output restored PLPs.

Accordingly, blocks following the multiplexer 211160 in the MIMOreceiver perform signal processing of one stream. That is, themultiplexer 211160 functions as the merger.

FIG. 27 illustrates a MIMO transmitter and a MIMO receiver according toanother embodiment of the present invention.

The MIMO transmitter and the MIMO receiver of FIG. 27 collectivelycorrespond to a case of performing MIMO communication by each using 2antennae. Most particularly, in case of the transmitter, this embodimentof the present invention corresponds to an example wherein themodulation method of each input signal is different from one another.More specifically, in this embodiment, the modulation methods for eachof the 2 input signals that is used in order to transmit the inputsignals through 2 antennae respectively correspond to the M-QAM typemodulation and the N-QAM type modulation (e.g., BPSK+QPSK orQPSK+16-QAM, etc.). However, hereinafter, with respect to the operationsof the demultiplexer, the embodiment of the present invention willhereinafter be described in detail along with the descriptions onQPSK+QPSK, QPSK+16-QAM, and 16-QAM+16-QAM.

FIG. 27 shows a case when the QAM types of the input signal and oroutput signal are different from one another. And, accordingly, theoperations of the device are similar to the operations of the case shownin FIG. 25. Therefore, only the operations that are different from FIG.25 and FIG. 26 will hereinafter be omitted for simplicity.

The MIMO transmitter may include a BICM module 212010, a frame builder212020, a frequency interleaver 212030, and an OFDM generator 212040.And, the BICM module 212010 may include an FEC encoder 212050, a bitinterleaver 212060, a demux (or demultiplexer) 212070, a symbol mapper212080, a MIMO encoder 212090, and a time interleaver 212100.

The MIMO receiver may include an OFDM demodulator 212110, a frequencydeinterlever 212120, a frame parser 212130, a time deinterleaver 212140,an MIMO decoder 212150, a multiplexer 212160, a bit deinterleaver212170, and an FEC decoder 212180. And, the time deinterleaver 212140,the MIMO decoder 212150, the multiplexer 212160, the bit deinterleaver212170, and the FEC decoder 212180 perform an inverse process of theBICM module. Hereinafter, this may be referred to a BICM decoding module212190.

More specifically, unlike FIG. 26, the MIMO encoder 212090 of FIG. 27 ispositioned between the symbol mapper 212080 and the time interleaver212100. The MIMO transmission data that are being transmitted inparallel may be processed in parallel and transmitted by multiple timeinterleavers 212100, frame builders 212020, frequency interleaver212030, and OFDM generators 212040 or by a time interleaver 212100, aframe builder 212020, and an OFDM generator 212040, which internallyprocess data in parallel, so as to be transmitted afterwards. In theembodiment using 2 antennae, as shown in FIG. 27, each of the timeinterleaver 212100, the frame builder 212020, frequency interleaver212030, and the OFDM generator 212040 may be provided in pairs, so as tobe capable of processing data, which are being outputted from the MIMOencoder 212090.

In the MIMO receiver of FIG. 27, the MIMO decoder 212150 is positionedbetween the time interleaver 212140 and the multiplexer 212160.Accordingly, the OFDM demodulator 212110, the frequency deinterleaver212120, the frame parser 212030, the time deinterleaver 212140 mayprocess a MIMO signal, which is received through multiple antennae,through multiple paths in symbol units. And, the MIMO decoder 212150converts symbol-unit data to LLR bit data and outputs the converteddata. In the embodiment shown in FIG. 12, a plurality of the OFDMdemodulators 212110, the frequency deinterleavers 212120, the frameparsers 212130, and the time deinterleavers 212140 may be provided. And,by being equipped with a memory that can perform the above-describedparallel processing, the above-described plurality of blocks may bereplaced with single blocks. Since the frequency deinterleaver 212120,the frame parser 212130, and the time deinterleaver 212140 cancollectively process the symbol-unit data, the complexity or requiredmemory size may be reduced, as compared with the embodiment of FIG. 26,which processes the LLR bit information.

Referring to FIG. 26 to FIG. 27, the MIMO transmitter may also transmitinformation indicating the QAM type of input signals, which are usedwhen performing MIMO encoding. More specifically, information indicatingthe QAM type of 1^(st) input signal and 2^(nd) input signal, which areoutputted from the frame builder, may transmit through a preamble part.According to the embodiment of the present invention, the 1^(st) inputsignal and the 2^(nd) input signal may either have the same QAM type, ormay have different QAM types. In this case, the MIMO decoder may use theinformation indicating the QAM type of the input signals, which areincluded in the reception signal, so as to perform MIMO decoding and tooutput QAM type output signals. However, such QAM type output signalsinclude bit unit data, and such bit unit data correspond to a softdecision value indicating the above-described bit-unit probability (orlikelihood). Such soft decision values may then be converted to harddecision values by performing FEC decoding.

A transmission frame according to present invention may include apreamble region, a data symbol region. In this case, the presentinvention may additionally allocate a preamble symbol to the preambleregion within a transmission frame. Hereinafter, the additional preamblesignal will be referred to as an AP1 symbol (Additional Preamble symbol)for simplicity in the description of the present invention. In order toenhance the detection performance for detecting a mobile broadcast(i.e., NGH) signal, in a considerably low SNR condition or atime-selective fading condition, at least one or more AP1 symbol isadded to the transmission frame.

Accordingly, in a transmission frame according to the present invention,the preamble region is configured of a P1 symbol, at least one or moreAP1 symbols, and at least one or more P2 symbols. And, the data regionmay be configured of a plurality of data symbols (or data OFDM symbols).The AP1 symbol may be positioned between the P1 symbol and the first P2symbol within the preamble region of the transmission frame. Morespecifically, the P1 symbol and the AP1 symbol may be transmittedconsecutively within single transmission frame or may be transmittednon-consecutively within single transmission frame according to theintention of a designer.

According to the embodiment of the present invention, the P1 symbol andthe AP1 symbol may be inserted for each transmission frame by a P1insertion module, which is included in the OFDM generator of thetransmitter. More specifically, the P1 insertion module may insert atleast 2 or more preamble symbols in each transmission frame. Accordingto another embodiment of the present invention, an AP1 insertion modulemay be added behind (or after) the P1 insertion module, and an AP1symbol may be inserted by the AP1 insertion module. As described in theembodiment of the present invention, when at least 2 or more preamblesymbols are used, the present invention is advantageous in that thepresent invention can be more robust against a burst fading effect,which may occur in a mobile fading environment, and that a signaldetection performance can be enhanced.

The AP1 symbol may be generated through the described processes aboveand may have a different structure from a conventional P1 symbol.

FIG. 28 illustrates an exemplary super frame structure for transmittingan additional broadcast signal according to the present invention.

A transmission frame configured to transmit an additional broadcastsignal within the super frame, e.g., a mobile broadcast signal, may bean additional transmission frame as described in FIG. 14, and mayinclude a P1 symbol, an AP1 symbol, at least one or more P2 symbols, anda plurality of data symbols, as shown in FIG. 28. Herein, the P1 symboltransmits P1 signaling information, the AP1 symbol transmits AP1signaling information, and the P2 symbol transmits the L1 signalinginformation. Hereinafter, the detail description of the symbols that areidentical to those described in FIG. 15 will be omitted for simplicity.And, only the AP1 symbol will be described in detail. The AP1 signalinginformation being transmitted by the AP1 symbol may include anadditional transmission parameter. According to the embodiment of thepresent invention, the AP1 signaling information may include patterninformation of a pilot, which is inserted in the correspondingtransmission frame. When the L1-pre-signaling information is spread tothe data region of the transmission frame, the AP1 signaling informationfurther includes information required for decoding the L1 signalinginformation spread to the data region of the transmission frame.

FIG. 29 illustrates a block diagram showing an exemplary structure of anOFDM generator, which is included in the transmitter, for inserting theAP1 symbol according to an embodiment of the present invention. The OFDMgenerator of FIG. 29 shows an example of transmitting a broadcast signalthrough 2 transmission antennae by using the MISO or MIMO method.

The OFDM generator of FIG. 29 is almost the same as the OFDM generator101500 shown in FIG. 6. However, the OFDM generator of FIG. 29 isdifferent from the OFDM generator 101500 shown in FIG. 6, in that theOFDM generator of FIG. 29 includes an MISO/MIMO encoder 302110 insteadof the MISO encoder 106100, and 2 API symbol insertion modules 302171,302172. Hereinafter, the detailed description for the blocks that areidentical to the blocks included in the OFDM generator 101500 shown inFIG. 6 will be omitted for simplicity. And, only the MISO/MIMO encoder302110 and the 2 API symbol insertion modules 302171, 302172 will bedescribed in detail.

In order to perform transmission through 2 transmission antennae, theMISO/MIMO encoder 302110 may perform MISO and/or MIMO encoding on thesignals being inputted through each path so that transmission diversitycan be gained. The pilot insertion module may insert a pilot of apre-decided pilot pattern in a respective position within thetransmission frame and may then transmit the processed frame. And, inthis case, the pilot pattern information may be signaled to AP1signaling information, or may be signaled to L1 signaling information.Furthermore, the pilot pattern information may also be signaled to bothAP1 signaling information and L1 signaling information.

The API symbol insertion modules 302171, 302172 may respectively insertan AP1 symbol after the P1 symbol, which are then transmitted to theDAC. For example, the AP1 symbol may transmit AP1 signaling information.

Meanwhile, when a pilot is inserted in each transmission frame andtransmitted by the pilot insertion modules 302121, 302122 included inthe OFDM generator, the receiver may detect the pilot and use thedetected pilot in frame synchronization, frequency synchronization, timesynchronization, channel estimation, transmission mode recognition, andso on.

The pilot according to the present invention may be divided into 2different types, one being a scattered pilot and the other beingcontinual pilot. More specifically, the scattered pilot is used toenable the receiver to estimate and compensate for any influence causedby a radio channel. And, the continual pilot to enable the receiver toremove any accurate frequency synchronization or phase error.

In the present invention, a plurality of scattered pilot patterns mayexist. And, according to the embodiment of the present invention, amongthe plurality of scattered pilot patterns, one scattered pilot patternmay be selected in accordance with an FFT size and a guide interval (GI)size, so as to be inserted in OFDM symbols of a transmission frame andtransmitting the pilot-inserted symbols. More specifically, according tothe embodiment of the present invention, when the present invention usesthe MIMO method, among 9 scattered pilot patterns (PP1˜PP9), onescattered pilot pattern is selected based upon the FFT size and the GIsize, so as to be inserted in the OFDM symbols of the correspondingtransmission frame.

In the description of the present invention, according to the embodimentof the present invention, 1 k, 2 k, 4 k, 8 k, and 16 k may be used asthe FFT size, and 1/128, 1/32, 1/16, 19/256, ⅛, 19/128, and ¼ may beused as the GI size. The FFT size refers to a number of subcarriersconfiguring a single OFDM symbol. And, the GI size refers to a ratiobeing occupied by the GI in a single OFDM symbol. Therefore, the lengthof an OFDM symbol may vary depending upon the FFT size and GI size.

The GI size may vary in a super frame unit, and the GI size informationmay be signaled to a GUARD_INTERVAL field of the L1 pre signalinginformation. That is, the GUARD_INTERVAL field indicates a GI of acurrent super frame. And, the pilot pattern information, which is beinginserted in the current transmission frame, may be signaled to aPILOT_PATTERN field of the L1 pre signaling information and/or aPILOT_PATTERN field the AP1 signaling information. In singletransmission frame, an FFT size of P2 symbols within the preamble regionis identical to that of OFDM symbol within the data region. Furthermore,FFT size information of the transmission frame is signaled in an S2field of P1 signaling information. For example, when a preamble formatcorresponds to a preamble (i.e., MISO or SISO) of a conventionaltransmission frame or an additional transmission frame, an FFT size anda portion of information about GI of P2 symbols and data symbols in thecorresponding transmission frame are signaled in an S2 field 1. Herein,the S2 field 1 means a first 3-bit of the S2 field. In other words, insingle transmission frame, the P2 symbol has the same FFT size and GIsize as the data symbols.

FIG. 30 illustrates an exemplary structure of a P1 symbol and anexemplary structure of an AP1 symbol according to an embodiment of thepresent invention. FIG. 30 shows an example of generating an AP1 symbolby modifying the P1 symbol.

In FIG. 30, P1 symbol, which is shown on the left side, is generated byhaving each of a front portion and an end portion of an effective (orvalid) symbol copied, by having a frequency shift performed as much as+f_(sh), and by having the frequency-shifted copies respectivelypositioned at a front portion (C) and an end portion (B) of theeffective symbol (A). In the present invention, the C portion will bereferred to as a prefix, and the B portion will be referred to as apostfix. More specifically, P1 symbol is configured of a prefix portion,an effective symbol portion, and a postfix portion.

In FIG. 30, AP1 symbol, which is shown on the right side, is generatedby having each of a front portion and an end portion of an effective (orvalid) symbol copied, by having a frequency shift performed as much as−f_(sh), and by having the frequency-shifted copies respectivelypositioned at a front portion (F) and an end portion (E) of theeffective symbol (D). In the present invention, the F portion will bereferred to as a prefix, and the E portion will be referred to as apostfix. More specifically, AP1 symbol is configured of a prefixportion, an effective symbol portion, and a postfix portion.

Herein, the two frequency-shift values +f_(sh)−f_(sh), which are used inthe P1 symbol and the AP1 symbol, may have the same absolute value yetbe given opposite signs. More specifically, the frequency-shift isperformed in opposite directions. And, the lengths C and F, which arecopied to the front portion of the effective symbol, may be set to havedifferent values. And, the lengths B and E, which are copied to the endportion of the effective symbol, may be set to have different values.Alternatively, the lengths C and F may be set to have different values,and the lengths B and E may be set to have the same value, or viceversa. According to another embodiment of the present invention, aneffective symbol length of the P1 symbol and an effective symbol lengthof the AP1 symbol may be differently determined. And, according to yetanother embodiment of the present invention, a CSS (Complementary SetSequence) may be used for tone selection and data scrambling within theAP1 may be scrambled by AP1.

According to the embodiment of the present invention, the lengths of Cand F, which are copied to the front portion of the effective (or valid)symbol, may be set to have different values, and the lengths of B and E,which are copied to the end portion of the effective (or valid) symbol,may also be set to have different values.

The C,B,F,E lengths according to the present invention may be obtainedby using Equation 9 shown below.

Length of C(T _(c))={Length of A(T _(A))/2+30}

Length of B(T _(B))={Length of A(T _(A))/2−30}

Length of E(T _(F))={Length of D(T _(D))/2+15}

Length of E(T _(E))={Length of D(T _(D))/2−15}  Equation 9

As shown in Equation 9, P1 symbol and AP1 symbol have the same frequencyshift value. However, each of the P1 symbol and the AP1 symbol are givenopposite signs. Additionally, in order to determine the lengths of C andB, the present invention determines an offset value being added to orsubtracted from a value corresponding to the length of A (T_(A))/2. And,in order to determine the lengths of F and E, the present inventiondetermines an offset value being added to or subtracted from a valuecorresponding to the length of D (T_(D))/2. Herein, each of the offsetvalues is set up differently. According to the embodiment of the presentinvention, the offset value of P1 symbol is set to 30, and the offsetvalue of AP1 symbol is set to 15. However, the values given in theabove-described examples are merely exemplary. And, therefore, it willbe apparent that the corresponding values may easily be varied orchanged by anyone skilled in the art. Thus, the present invention willnot be limited only to the values presented herein.

According to the present invention, by generating AP1 symbol and an AP1symbol to configure the structure shown in FIG. 30, and by inserting thegenerated symbols to each transmission frame, the P1 symbol does notdegrade the detection performance of the AP1 symbol, and, conversely,the AP1 symbol does not degrade the detection performance of the P1symbol. Additionally, the detection performance of the P1 symbol isalmost identical to the detection performance of the AP1 symbol.Furthermore, by configuring the symbols so that the P1 symbol and theAP1 symbol have similar symbol structures, the complexity level of thereceiver may be reduced.

At this point, the P1 symbol and the AP1 symbol may be transmittedconsecutively, or each of the symbols may be allocated to differentpositions within the transmission frame and may then be transmitted.And, in case the P1 symbol and AP1 symbol are each allocated to adifferent position within the transmission frame, so as to betransmitted, a high time diversity effect may be gained with respect tothe preamble symbol. According to the embodiment of the presentinvention, the P1 symbol and the AP1 symbol are consecutivelytransmitted.

FIG. 31 illustrates an OFDM demodulator according to yet anotherembodiment of the present invention. The OFDM demodulator shown in FIG.31 is almost identical to the OFDM demodulator 107100, which isdescribed with reference to FIG. 8. However, the OFDM demodulator ofFIG. 31 is different from the OFDM demodulator 107100 of FIG. 8 in thatthe OFDM demodulator includes AP1 symbol detection modules 306602,306612. Therefore, detailed description on the blocks that are identicalto the blocks included in the OFDM demodulator of FIG. 8 will be omittedfor simplicity. And, only the AP1 symbol detection modules 306602,306612 will be briefly described. Herein, among the digital broadcastsignals, the AP1 symbol detection modules 306602, 306612 may detect anddecode AP1 symbols that transmit (or carry) AP1 signaling information,The receiver may use the AP1 signaling information so as to gain pilotpattern information of the current transmission frame.

Hereinafter, when the data configuring a service of the broadcast signalcorresponds to a TS (Transport Stream) format or an IP (InternetProtocol) stream/packet, the description of the present invention seeksto provide a signaling method that can perform transmission, whileensuring backward compatibility with the conventional terrestrialtransmission method. As an example of the present invention, the TS maycorrespond to an MPEG-2 TS.

FIG. 32 illustrates a broadcasting system according to an embodiment ofthe present invention.

FIG. 32 illustrates an exemplary broadcasting system configured totransmit a broadcast signal, so that each receiver can selectivelyreceive a broadcast signal best-fitting the characteristics of therespective receiver, when a broadcast station transmits a broadcastsignal.

When the broadcasting system according to the present invention isconfigured as shown in FIG. 32, a mobile receiver 501100, such as amobile phone, may select a transmission frame having a high mobilereceiving performance and may receive the selected transmission frame.And, a fixed-type receiver 501200 including a television receiver usedin general households may select a transmission frame having highpicture quality indoor receiving performance and may receive theselected transmission frame. And, a movable receiver 501300 including amovable television receiver may select a transmission having an adequatelow resolution mobile receiving performance and an adequate high picturequality indoor receiving performance and may receive the selectedtransmission frame.

According to an exemplary embodiment of the present invention, thebroadcasting system according to the present invention may use SVC(Scalable Video Coding) so as to be capable of receiving a requiredbroadcast frame based upon the characteristics of the receiver.

FIG. 33 illustrates a block view showing a process of receiving a PLPbest-fitting the purpose of a receiver respective to the broadcastingsystem according to an embodiment of the present invention.

As shown in FIG. 33, one transmission frame 502100 may include aplurality of PLPs.

A PLP corresponds to a transmission data unit that is identified in thephysical layer. Each PLP may transmit data having the same attribute ofthe physical layer, which is being processed in the transmission path.Additionally, according to the embodiment of the present invention thephysical parameter may be differently set up for each PLP. Moreover,according to the embodiment of the present invention, data correspondingto a service may be categorized by components, such as video, audio, andso on, and may transmit the data corresponding to each component toseparate PLPs. Furthermore, the component of the present invention maybe used to indicate that the corresponding data are included in thecomponent.

As shown in FIG. 33, the plurality of PLPs 502200, i.e., PLP1 to PLP4,being included in a single transmission frame 502100 may each carry oneservice. Herein, the present invention may use an SVC (Scalable VideoCoding) method to perform encoding on a moving picture, so that a wanted(or desired) picture quality can be hierarchically generated. Then, eachmoving picture may be transmitted through the base layer and theenhancement layer. The base layer may transmit video data respective toan image having basic picture quality, and the enhancement layer maytransmit additional video data that can recover an image having higherlayer picture quality. Additionally, hereinafter, a SVC target may notcorrespond only to the video data. And, the base layer may be used toindicate data that can provide a basic service including the basic image(or video)/voice (or audio)/data corresponding to the base layer, andthe enhancement layer may be used to indicate data that can provide ahigher service including higher layer image (or video)/voice (oraudio)/data corresponding to the enhancement layer.

Hereinafter, the definition of the base layer may include video datacorresponding to the base layer, and the definition of the enhancementlayer may include video data corresponding to the enhancement layer.

As shown in FIG. 33, PLP1 according to the present invention maytransmit the base layer, PLP2 may transmit the enhancement layer, PLP3may transmit an audio stream, and PLP4 may transmit a data stream.

In the present invention, the physical parameters may be adjusted inaccordance with the characteristics of the data included in each PLP soas to differently set up the mobile receiving performance or the datacommunication performance, thereby enabling the receiver to selectivelyreceive the required PLP in accordance with the characteristics of eachreceiver. An example of the same will hereinafter be described indetail.

As shown in FIG. 33, since PLP1, which transmits the base layer, isrequired to be received by both the general fixed type receiver 502300and the mobile receiver 502400, the transmitting unit may set-up (ordetermine) physical parameters for a high mobile receiving performancewith respect to PLP1 and may transmit the determined physicalparameters.

Additionally, PLP2, which transmits the enhancement layer, cannot bereceived by the mobile receiver 502400 due to its lower mobile receivingperformance, as compared to PLP1. Nevertheless, in order to allow thefixed type receiver 502300, which requires high resolution and highpicture quality broadcast contents to be received, the transmitting unitmay set-up (or determine) physical parameters for a high mobilereceiving performance with respect to PLP2 and may transmit thedetermined physical parameters.

Therefore, as shown in FIG. 33, the mobile receiver 502300 may receivePLP1, which transmits the base layer having a high mobile receivingperformance, and may also receive PLP3 and PLP4, which transmit audioand data stream, so as to provide services with general resolution.

Conversely, in order to receive high picture quality broadcast contents,the fixed type receiver 502400 may collectively receive PLP1 and PLP2,which transmit transport streams related to an enhancement layer havinghigh resolution, and PLP3 and PLP4. Thus, by receiving a large amount ofdata, the fixed type receiver 502400 may provide high picture qualityservices.

FIG. 34 illustrates a transmission frame according to an embodiment ofthe present invention.

As shown in FIG. 34, the transmission frame may include a P1 signalinginformation region 503100, an L1 signaling information region 503200, acommon PLP region 503300, scheduled and interleaved multiple PLP regions503400, and an auxiliary data region 503500. In the description of thepresent invention, the common PLP region 503300 may also be referred toas an L2 signaling information region.

The signaling information corresponds to information being used by thereceiver for recovering data included in multiple PLP regions. Herein,the signaling information may include P1 signaling information, L1signaling information, and L2 signaling information. And, the P1signaling information region 503100, the L1 signaling information region503200, and the common PLP region 503300 may be collectively referred toas a preamble. Moreover, only the P1 signaling information region 503100and the L1 signaling information region 503200 may be collectivelyreferred to as a preamble.

Hereinafter, each region will be described in detail.

The P1 signaling information region 503100 may include P1 signalinginformation, which includes information for identifying (or recognizing)the preamble itself.

The L1 signaling information region 503200 may include L1 signalinginformation, which includes information required by the receiver forprocessing the PLP within the transmission frame.

The L2 signaling information 503300 may include L2 signalinginformation, which includes information that can be commonly applied tomultiple PLPs. The L2 signaling information according to the presentinvention may include PSI/SI (Program and System Information/SignalingInformation). More specifically, in case the broadcast signalcorresponds to a TS format, the L2 signaling information may includenetwork information, such as an NIT (Network Information Table), and PLPinformation, and may also include service information such as an SDT(Service Description Table), an EIT (Event Information Table), and a PMT(Program Map Table)/PAT (Program Association Table). And, depending uponthe intentions of the system designer, service information, such as SDTand PMT/PAT, may be included in multiple PLP regions 503400, so as to betransmitted.

If the broadcast signal corresponds to an IP format, the L2 signalinginformation may include an IP information table, such as an INT (IP/MACnotification table). The plurality of scheduled and interleaved PLPregions 503400 may transmit service components, such as audiocomponents, video components, data components, and so on, which areincluded in a service, through multiple PLPs. Herein, the PLP regions503400 may also include PSI/SI, such as PMT/PAT.

The receiver may use the information included in the P1 signalinginformation region 503100 so as to decode the L1 signaling informationregion 503200, thereby gaining (or acquiring) information on thestructure of the PLPs included in the transmission frame and informationon the frame configuration. Most particularly, by referring to theinformation included in L1 signaling information region 503200 or the L2signaling information region 503430, the receiver may be capable ofknowing a specific PLP, through which each of the service componentsbeing included in the service is transmitted. The above-describeddecoding process may be performed by the BICM decoder 107300 of thebroadcast signal receiver according to the present invention. The BICMencoder 101300 of the broadcast signal transmitter according to thepresent invention may perform encoding on signaling informationassociated with the broadcast service and may transmit the L1 signalinginformation, so that the receiver can perform decoding on the receivedinformation.

In case the L1 signaling information region 503200 includes informationon the service components, the receiver may receive the transmissionframe and may recognize and apply the information on the servicecomponents at the same time. However, since the size of the L1 signalinginformation region 503200 is limited, the amount (or size) of theinformation on the service components that can be transmitted from thetransmitting end may also be limited. Therefore, the L1 signalinginformation region 503200 it adequate for receiving the transmissionframe and recognizing the information on the service components at thesame time, and for transmitting the information that can be applied tothe receiver.

In case the L2 signaling information region 503300 included informationon the service components, the receiver may acquire (or gain)information on the service components, after the decoding process of theL2 signaling information region 503300 is completed. Therefore, whilethe receiver receive the transmission frame, the receiver cannotrecognize or change (or modify) the information on the servicecomponents at the same time. However, since the size of the L2 signalinginformation region 503300 is larger than the size of the L1 signalinginformation region 503200, data respective to a large number of servicecomponents may be transmitted. Accordingly, the L2 signaling informationregion 503300 is adequate for transmitting general informationrespective to the service components.

According to the embodiment of the present invention, the presentinvention uses both the L1 signaling information region 503200 and theL2 signaling information region 503300. More specifically, while the L1signaling information region 503200 receives the transmission frame on aPLP level, such as a high mobile performance and a high speed datacommunication characteristic, the L1 signaling information region 503200may also transmit information of the service components, which can bechanged (or modified or varied) at any time during the transmission ofthe broadcast signal, at the same time. Furthermore, the L2 signalinginformation region 503300 may transmit information on the servicecomponents, which are included in the corresponding service, and generalinformation on the channel reception.

FIG. 35 illustrates a list of fields being included in the L1 signalinginformation region of FIG. 34 according to the exemplary embodiment ofthe present invention.

FIG. 35 shows exemplary fields being included in an NUM_PLP loop, whichis included in the L1 signaling information region 503200 of FIG. 34.According to the embodiment of the present invention, in the descriptionof the present invention, the NUM_PLP loop shown in FIG. 34 is includedin a table being included in a dynamic block of the L1-post signalinginformation, which is described above with reference to FIG. 16.

The NUM_PLP loop may include fields associated to each PLP of themultiple PLPs included in the transmission frame. And, although it isnot shown in the drawing, the number of PLPs may be pre-determined inanother field of the L1 signaling information region 503200.Additionally, in the description of the present invention, a field mayalso be referred to as information, and this may be commonly applied toall exemplary embodiments of the present invention.

As shown in FIG. 35, the NUM_PLP loop may include a PLP_ID field, aPLP_GROUP_ID field, a PLP_TYPE field, a PLP_PAYLOAD_TYPE field, aPLP_COMPONENT_TYPE field, a PLP_COD field, a PLP_MOD field, and aPLP_FEC_TYPE field. Hereinafter, each field will be described in detail.

The PLP_ID field has the size of 8 bits and may identify each PLP.

The PLP_GROUP_ID field also has the size of 8 bits and may identify aPLP group including the corresponding PLP. In the description of thepresent invention, according to the exemplary embodiment of the presentinvention, the PLP group may also be referred to as an LLP(Link-Layer-Pipe), and the PLP_GROUP_ID field may also be referred to asan LLP_ID field. Most particularly, the NIT, which will be describedlater on in more detail, may include a PLP_GROUP_ID field, which isidentical to the PLP_GROUP_ID field, which is included in the L1signaling information, and the NIT may also include a transport streamid field, which is used for identifying a transport stream associated tothe PLP group. Accordingly, by using the NIT, the receiver may becapable of knowing (or recognizing) a specific PLP group to which aspecific transport stream is associated. More specifically, in order tosimultaneously decode transport streams being transmitting through therespective PLPs having the same PLP_GROUP_ID, transport streams that areindicated by the transport stream id field of the NIT may be merged, soas to recover a single service stream.

Accordingly, when the broadcast signal is being transmitted in a TSformat, the receiver may merge PLPs having the same PLP_GROUP_ID fieldand may, then, recover the original (or initial) transport stream.

Alternatively, if the broadcast signal is being transmitted in an IPformat, the receiver may use the PLP_GROUP_ID field so as to locate andfind the service components associated with a single service. And, bymerging such service components, a single service may be recovered.Accordingly, the receiver may simultaneously receive multiple PLPshaving the same PLP_GROUP_ID.

The PLP_TYPE field has the size of 3 bits and may identify a PLP beingincluded in multiple PLP groups and a group PLP being included in asingle group.

The PLP_PAYLOAD_TYPE field has the size of 5 bits and may indicatewhether a transport packet included in the PLP is configured in a TSformat or in an IP format.

The PLP_COMPONENT_TYPE field has the size of 8 bits. And, as a fieldthat can identify the type of the data (or service component) beingtransmitted through the PLP, the receiver may use the PLP_COMPONENT_TYPEfield, so as to be capable of identifying whether the component type ofthe broadcast service, which is being transmitted through the PLP,corresponds to video data, video extension data, audio data, or data.The PLP_COD field corresponds to a 3-bit field and may indicate a codingrate of the PLP. In the description of the present invention, examplesof the coding rate may include ½, ⅗, ⅔, ¾, and so on.

The PLP_MOD field has the size of 3 bits and may indicate a modulationtype of the PLP. In the description of the present invention, examplesof the modulation type may include QPSK, 16QAM, 64QAM, 256QAM, and soon.

The PLP_FEC_TYPE field corresponds to a 2-bit field, which may indicatean FEC (Forward Error Correction) type of the PLP.

The PLP_GROUP_ID field, the PLP_TYPE field, and the PLP_COMPONENT_TYPEfield may be used in order to signal the correlation between the PLP andthe service components, and the correlation between the transport streamand service components. Additionally, the PLP_COD field and the PLP_MODfield may be used for signaling an operation characteristic, such asmobile performance and data communication characteristic, of the PLP.

FIG. 36 illustrates a list of fields being included in the L1 signalinginformation region of FIG. 34 according to another exemplary embodimentof the present invention.

FIG. 36 shows exemplary fields being included in an NUM_PLP loop, whichis included in the L1 signaling information region 503200 of FIG. 34.According to the embodiment of the present invention, in the descriptionof the present invention, the NUM_PLP loop shown in FIG. 34 is includedin a table being included in a dynamic block of the L1-post signalinginformation, which is described above with reference to FIG. 16.

The NUM_PLP loop may include fields associated to each PLP of themultiple PLPs included in the transmission frame. And, although it isnot shown in the drawing, the number of PLPs may be pre-determined inanother field of the L1 signaling information region 503200.Additionally, in the description of the present invention, a field mayalso be referred to as information, and this may be commonly applied toall exemplary embodiments of the present invention.

The fields included in the NUM_PLP loop shown in FIG. 36 are identicalto the fields included in the NUM_PLP loop shown in FIG. 35. However,the NUM_PLP loop shown in FIG. 36 may further include a PLP_PROFILEfield. Hereinafter, detailed description of the fields that areidentical to the fields described with reference to FIG. 35 will beomitted for simplicity. And, therefore, only the PLP_PROFILE field willbe described in detail.

The PLP_PROFILE field has the size of 8 bits and may identify whetherthe corresponding PLP is a mandatory (or required) PLP or an optional(or selective) PLP. For example, in case the component being transmittedthrough the PLP is identified (or distinguished) as a base layer or anenhancement layer, the PLP transmitting the base layer becomes themandatory PLP, and the PLP transmitting the enhancement layer becomesthe optional PLP. More specifically, depending upon the receivercharacteristic, such as a mobile receiver, an HD receiver, and so on,the receiver may use the PLP_PROFILE field so as to verify by whichreceiver the component of the broadcast service being transmitted to thecurrent PLP may be used, and depending upon the receiver characteristic,the receiver may determine whether or not to receive the current PLP.

In the description of the present invention, a signaling method forsignaling the PLP or for signaling the correlation between the PLP andthe service components by using the PLP_ID field, the PLP_GROUP_IDfield, the PLP_COMPONENT_TYPE field, and the PLP_PROFILE field.

Hereinafter, the present invention provides a signaling method accordingto 4 different exemplary embodiments of the present invention. The 4different exemplary embodiments may be divided into cases when thebroadcast signal is being transmitted in a TS format and cases when thebroadcast signal is being transmitted in an IP format. In thedescription of the present invention, the first exemplary embodiment tothe third exemplary embodiment correspond to a signaling method whereinthe broadcast signal is transmitted in the TS format, and the fourthexemplary embodiment corresponding to a signaling method wherein thebroadcast signal is transmitted in the IP format.

Each exemplary embodiment of the present invention will be described indetail as presented below.

The first embodiment of the present invention corresponds to a signalingmethod enabling the receiver to merge PLPs included in the same PLPgroup by using the correlation between the PLP group, which is includedin the L1 signaling information region, and a service, thereby enablingthe receiver to recover a transport stream.

Just as in the first embodiment of the present invention, in addition toenabling the receiver to merge PLPs included in the same PLP group byusing the correlation between the PLP group, which is included in the L1signaling information region, and a service, thereby enabling thereceiver to recover a transport stream, the second embodiment of thepresent invention corresponds to a signaling method also enabling thereceiver to selectively receive desired PLPs in accordance with thereceiver characteristic, by using the correlation between a component,which configures the service included in the PLP, and a service.

The third embodiment of the present invention is similar to the secondembodiment of the present invention. However, the third embodiment ofthe present invention corresponds to a signaling method enablinginformation associated with the component, which configures the sameservice, to be transmitted through a base PLP, and enabling the receiverto selectively receive a PLP, which configures the service desired bythe receiver, in the physical layer.

The fourth embodiment of the present invention corresponds to asignaling method respective to a case when the broadcast signal is beingtransmitted in an IP format. In the signaling method according to thefourth embodiment of the present invention, the receiver may merge thecomponent being transmitted by the PLPs included in the same PLP group,by using a correlation between a service and a PLP, which transmits thecomponents being included in the service, and then the receiver mayrecover a service.

Hereinafter, each exemplary embodiment of the present invention will bedescribed in detail.

FIG. 37 to FIG. 39 will hereinafter describe the first embodiment of thepresent invention.

FIG. 37 illustrates a conceptual view of a correlation between a serviceaccording to the first embodiment of the present invention and a PLPgroup.

In case of transmitting a broadcast signal of a TS format, the firstembodiment of the present invention corresponds to a signaling methodfor recovering a transport stream by acquiring a service ID from thereceiver, by using a PLP group ID associated to the acquired service ID,and by merging multiple PLPs being included in the same PLP group.

As shown in FIG. 37, the L1 signaling information region 505100according to the first embodiment of the present invention may includeinformation related to each of the multiple PLPs, i.e., a PLP_GROUP_IDfield, a PLP_ID field, and so on. Also, the L2 signaling informationregion 505200 may include an NIT and an SDT.

The NIT may include a PLP_GROUP_ID field, which is identical to thePLP_GROUP_ID field included in the L1 signaling information region505100, and a transport_stream_id field. By using these fields, thereceiver may be capable of knowing to which PLP group a specifictransport stream is correlated. Also, the SDT may include atransport_stream_id field, which is identical to the transport_stream_idincluded in the NIT, and a service_id field. By using these fields, thereceiver may be capable of differentiating (or identifying) each of theservices being transmitted through a specific transport stream.

Eventually, among the many services included in a specific transportstream, the receiver may identify the desired service by using theservice_id field, which is included in the SDT. And, by using thetransport stream id field and the PLP_GROUP_ID field, which are includedin the NIT, the receiver may identify a PLP group, which is related withthe specific transport stream. Thereafter, the receiver may receive aPLP having the same PLP_GROUP_ID field, which is included in the L1signaling information region 505100. More specifically, the receiver maymerge multiple PLPs, which are included in a PLP group being correlatedwith the desired service, so as to recover a transport stream.

Hereinafter, the fields, the NIT, and the SDT being included in the L1signaling information region 505100 according to the first embodiment ofthe present invention will be described in detail.

Since the L1 signaling information region 505100 according to the firstembodiment of the present invention includes the same fields, which aredescribed with reference to FIG. 3, the detailed description of the samewill be omitted for simplicity.

The NIT corresponds to a table transmitting information related to thephysical structure of a multiplexer/transport stream being transmittedthrough the network, and diverse information respective to thecharacteristics of the network itself. The receiver may gain informationon the transport stream from the NIT.

The NIT according to the first embodiment of the present invention mayinclude a network_id field, a transport_stream_id field, and adelivery_system_descriptor loop.

Hereinafter, each field included in the NIT shown in FIG. 37 will bedescribed in detail.

The network_id field is used for identifying a network through which thecurrent broadcast signal is being transmitted.

The transport_stream_id field is used for identifying a transport streamthat is currently being transmitted.

The delivery system descriptor field may include fields required (ornecessary) for matching the transport stream with the PLP and thetransmitting system. Most particularly, the delivery_system_descriptorfield according to the present invention may include a PLP_GROUP_IDfield that is identical to the PLP_GROUP_ID field included in the L1signaling information.

Detailed contents of the delivery_system_descriptor field will bedescribed later on.

The delivery_system_descriptor field according to the first embodimentof the present invention may include a PLP_ID loop, which is included inthe L1 signaling information region 505100. In this case, the PLP_IDloop may include diverse fields related to each of the plurality of PLPsincluded in the transmission frame.

A system_id field is used for identifying a system that is unique to thebroadcast network performing transmission.

A system_parameters( ) field may include parameters indicating thetransmitting system characteristics, such as whether the communicationis performed in a SISO/MIMO mode, a bandwidth, a guard interval, atransmission mode, and so on.

A cell_parameters( ) field may include parameters indicating cellinformation, such as a center frequency, a cell identifier, and so on.

The SDT corresponds to a table including information on multipleservices, which are included in a single transport stream. The SDTaccording to the first embodiment of the present invention may include atransport_stream_id field, and a NUM_service loop. And, the NUM_serviceloop may include a service_id field.

Hereinafter, each field included in the SDT shown in FIG. 37 will bedescribed in detail.

Since the transport stream id field is identical to thetransport_stream_id field, which is included in the NIT, a detaileddescription of the same will be omitted for simplicity.

The service_id field is used for identifying multiple services includedin the transmission frame.

FIG. 38 illustrates an exemplary delivery system descriptor fieldaccording to the first embodiment of the present invention.

As described above, FIG. 38 shows a delivery_system_descriptor field ofthe NIT according to the first embodiment of the present invention.Herein, the delivery_system_descriptor field is used for connecting thePLP_GROUP_ID field of the L1 signaling information region 505100 to thetransport stream.

As shown in FIG. 38, the delivery_system_descriptor field may include adescriptor_tag field, a descriptor_length field, a system_id field, aPLP_GROUP_ID field, and a first loop.

The first loop is used when the descriptor_length field has a sizelarger than 3. And, in this case, the first loop may include asystem_parameters( ) field and a second loop.

The second loop may include a cell_parameters( ) field.

Hereinafter, each field will be described in detail.

The descriptor_tag field is used for identifying each descriptor.

The descriptor_length field is used for indicating a total length of thedata portion of each descriptor.

The system_id field is used for identifying a system that is unique tothe broadcast network performing transmission.

The PLP_GROUP_ID field may identify a PLP group that is to be matchedand merged with the transport stream id field. Since the essentialdetails of the PLP_GROUP_ID field are identical to those of thePLP_GROUP_ID field shown in FIG. 34, a detailed description of the samewill be omitted for simplicity.

Since the system_parameters( ) field included in the first loop and thecell_parameters( ) field included in the second loop are identical tothose described in FIG. 37, a detailed description of the same will beomitted for simplicity.

FIG. 39 illustrates a flow chart showing the process steps of a servicescanning method of the receiver according to the first embodiment of thepresent invention.

After receiving a TP type broadcast signal, the receiver may tune to anext channel (S507100). In this case, in order to receive a servicedesired by the user, the receiver requires information on the serviceincluded in the transmission frame, which is being transmitted throughthe respective channel. Although this process step is not shown in thedrawing, this process step may be performed by the tuner of the receiverand may be modified or varied in accordance with the intentions of thesystem designer.

Then, the receiver may decode the L1 signaling information region 505100included in the transmission frame, so as to acquire a PLP_ID, a PLPGroup ID, and a system ID, which are included in the transmission frame(S507200). The system ID may be included in a signaling informationregion other than the L1 signaling information region 505100.Thereafter, the receiver may identify the PLP groups by using thedecoded PLP Group ID, so as to select the desired PLP group, and maydecode the PLP including the L2 signaling information region 505200 andthe PSI/SI (S507300). This process step may be performed by the BICMdecoder 107300 of the broadcast signal receiver according to the presentinvention. And, more specifically, this process step may be performed bya second decoding block 110200. Respectively, the BICM encoder 101300 ofthe broadcast signal transmitter according to the present invention mayencode the signaling information, so as to generate and transmit L1signaling information. This is a detail that can be varied or modifiedby the intentions of the system designer.

The receiver may decode the NIT and the SDT included in the decoded L1signal information region 505200, and the receiver may also decode aPAT/PMT included in the PLP, thereby being capable of storing serviceinformation associated with the transmitting system and the PLPstructure (S507400). The service information according to the presentinvention may include a service ID for identifying a service. Thisprocess step may be performed by the BICM decoder 107300 of thebroadcast signal receiver according to the present invention. And, morespecifically, this process step may be performed by a first decodingblock 110100. This is a detail that can be varied or modified by theintentions of the system designer.

Subsequently, the receiver may determine whether or not the currentlyselected PLP group corresponds to the last PLP group (S507500).

Based upon the determined result, when it is determined that theselected PLP group does not correspond to the last PLP group, thereceiver may return to the process step S507300, so as to select thenext PLP group. Alternatively, when it is determined that the selectedPLP group corresponds to the last PLP group, the receiver may determinewhether or not the current channel corresponds to the last channel(S507600).

Then, based upon the determined result, when it is determined that thecurrent channel does not correspond to the last channel, the receivermay return to the process step S507100, so as to tune to the nextchannel. And, alternatively, when it is determined that the currentchannel corresponds to the last channel, the receiver may use the storedservice information so as to tune to a first service or a pre-setservice (S507700).

FIG. 40 to FIG. 42 will hereinafter describe the second embodiment ofthe present invention.

FIG. 40 illustrates a conceptual view of a correlation between a serviceaccording to the second embodiment of the present invention and a PLPgroup.

The first embodiment of the present invention corresponds to a signalingmethod using a PLP Group ID and a service ID. And, in this case, thereceiver may use a correlation between a service and a PLP group one aservice level, so as to recover a service.

However, as shown in FIG. 32, depending upon the characteristics of thereceiver, when a video layer is to be selectively received so as toprovide a high picture quality image, the signaling method according tothe first embodiment of the present invention is disadvantageous in thatthe information on a video stream, which is included in the PLP, cannotbe acquired.

Therefore, according to the second embodiment of the present invention,when receiving a TS format broadcast signal, in addition to thesignaling method using the correlation between a service and a PLPgroup, a signaling method that can determine the type of the currenttransport stream and that can acquire information related to thecomponents included in each PLP, thereby being capable of selectivelyreceiving the transport stream and the PLP based upon the acquiredinformation.

As shown in FIG. 40, the L1 signaling information region 508100according to the second embodiment of the present invention may includediverse information related to each of the multiple PLPs, i.e., aPLP_GROUP_ID field, a PLP_ID field, a PLP_COMPONENT_TYPE field, and soon. Also, the L2 signaling information region field 508200 may includean NIT and an SDT. Herein, the NIT may include a PLP_GROUP_ID field,which is identical to the PLP_GROUP_ID field included in the L1signaling information region 508100, and a transport stream id field. Byusing these fields, the receiver may be capable of knowing to which PLPgroup a specific transport stream is correlated. Also, the SDT mayinclude a transport_stream_id field, which is identical to thetransport_stream_id included in the NIT, and a service_id field. Byusing these fields, the receiver may be capable of differentiating (oridentifying) each of the services being transmitted through a specifictransport stream. Additionally, since the PMT include a program_numberfield, which matches with the service_id field included in the SDT, thereceiver may use the program_number field so as to verify a programnumber included in the selected service. Moreover, since the PMTincludes a stream type field, a PLP_ID field, and a PLP_COMPONENT field,the receiver may determine the type of the current stream by using thestream type field. And, by using the PLP_COMPONENT field, the receivermay determine the type of the component included in the current PLP, soas to selectively receive the PLP.

Eventually, as described in the first embodiment of the presentinvention, the receiver may acquire the service_id field from the parsedSDT, so as to be capable of identifying a desired service, among aplurality of services included in a specific transport stream. Then, byusing the NIT, the receiver may identify a PLP group, which is relatedto the specific transport stream. Thereafter, the receiver may receive aPLP having a PLP_GROUP_ID field included in the L1 signaling informationregion 508100, thereby being capable of recovering a service stream.Additionally, the receiver may also use the component informationincluded in the PLP, so as to selectively receive the PLP and to becapable of providing an image best-fitting the receiver characteristic.

Hereinafter, the fields, the NIT, and the SDT being included in the L1signaling information region 508100 according to the second embodimentof the present invention will be described in detail.

Since the L1 signaling information region 508100 according to the secondembodiment of the present invention includes the same fields, which areincluded in the L1 signaling information region described with referenceto FIG. 35, and since the NIT and the SDT are identical to the NIT andSDT described with reference to FIG. 37, detailed description of thesame will be omitted for simplicity. The PMT corresponds to a tableincluding information indicating or identifying the positions of thestreams being included in each service.

The PMT according to the second embodiment of the present invention maybe transmitted through a PLP, and the transmitting end may process andtransmit the PMT as data. Furthermore, the PMT may also include aprogram_number field, and a PID loop.

Hereinafter, each field included in the PMT shown in FIG. 40 will bedescribed in detail.

A program_number field is used for identifying each program servicewithin the current transport stream. Herein, the program_number field ismatched with the service_id field of the SDT. The PID loop may include astream_type field, an elementary_PID field, and acomponent_id_descriptor field, which include information related to eachof the multiple packets.

A stream_type field is used for identifying the type of the streamthrough which the program is being transmitted. Examples of the streamstypes according to the present invention may include an SVC stream, anAVC stream, and so on.

An elementary_PID field is used for identifying a packet of an ES(Elementary Stream).

A component_id_descriptor field may include a PLP_ID field and aPLP_COMPONENT_TYPE field. Herein, since the PLP_ID field and thePLP_COMPONENT_TYPE field are identical to the PLP_ID field and thePLP_COMPONENT_TYPE field, which are included in the L1 signalinginformation region 508100, a detailed description of the same will beomitted for simplicity.

Therefore, when multiple stream types exist, the receiver may identify aspecific stream by using the stream type field and may select theidentified stream. Also, by using the PLP_COMPONENT_TYPE field, thereceiver may also determine whether the component being transmitted bythe PLP corresponds to a base layer or an enhancement layer, and thereceiver may then selectively receive or process the PLP in accordancewith the receiver characteristic.

FIG. 41 illustrates an exemplary component ID descriptor field accordingto the second embodiment of the present invention.

Herein, FIG. 41 corresponds to an exemplary component_id_descriptorfield, which is included in the PID loop of the PMT. Herein, thecomponent_id_descriptor field is being used for connecting thePLP_COMPONENT_TYPE field of the L1 signaling information region 508100to the transport stream.

The component_id_descriptor field may include a descriptor_tag field, adescriptor_length field, a system_id field, a PLP_ID field, and aPLP_COMPONENT_TYPE field. Herein, the PLP_ID field is used foridentifying a PLP that matches with a PID sub stream of thecorresponding stream type.

Since the contents of each field are identical to those described inFIG. 35 and FIG. 38, detailed description of the same will be omittedfor simplicity.

FIG. 42 illustrates a flow chart showing the process steps of a servicescanning method of the receiver according to the second embodiment ofthe present invention.

After receiving a TP type broadcast signal, the receiver may tune to anext channel (S510100). In this case, in order to receive a servicewanted (or desired) by the user, the receiver requires information onthe service included in the transmission frame, which is beingtransmitted through the respective channel. Although this process stepis not shown in the drawing, this process step may be performed by thetuner of the receiver and may be modified or varied in accordance withthe intentions of the system designer.

Then, the receiver may decode the L1 signaling information region 508100included in the transmission frame, so as to acquire a PLP_ID, a PLPGroup ID, and a system ID, which are included in the transmission frame(S510200). This process step may be performed by the BICM decoder 107300of the broadcast signal receiver according to the present invention.And, more specifically, this process step may be performed by a seconddecoding block 110200. Respectively, the BICM encoder 101300 of thebroadcast signal transmitter according to the present invention mayencode the signaling information, so as to generate and transmit L1signaling information. This is a detail that can be varied or modifiedby the intentions of the system designer.

Thereafter, the receiver may identify the PLP groups by using thedecoded PLP Group ID, so as to select the desired PLP group, and maydecode the PLP including the L2 signaling information region 508200 andthe PSI/SI (S510300). This process step may be performed by the BICMdecoder 107300 of the broadcast signal receiver according to the presentinvention. And, more specifically, this process step may be performed bya first decoding block 110100. Respectively, the BICM encoder 101300 ofthe broadcast signal transmitter according to the present invention mayencode the signaling information, so as to generate and transmit L1signaling information. This is a detail that can be varied or modifiedby the intentions of the system designer.

The receiver may decode the NIT and the SDT included in the decoded L1signal information region 508200, and the receiver may also decode aPAT/PMT included in the PLP, thereby being capable of storing serviceinformation associated with information on the structures of thetransmitting system and the PLP (S510400). The service informationaccording to the present invention may include a service ID foridentifying a service. This process step may be performed by the BICMdecoder 107300 of the broadcast signal receiver according to the presentinvention. And, more specifically, this process step may be performed bya first decoding block 110100. This is a detail that can be varied ormodified by the intentions of the system designer.

Additionally, the receiver may use the PLP_COMPONENT_TYPE field includedin the decoded PMT, so as to verify the type of the component beingtransmitted by the current PLP, and then the receiver may store thecomponent that is to be additionally received in accordance with thereceiver characteristics (S510500). More specifically, the receiver mayuse the above-described stream type and PLP_component_type information,so as to additionally receiver/store a component corresponding to theservice, which may be provided in accordance with the receivercharacteristic.

Subsequently, the receiver may determine whether or not the currentlyselected PLP group corresponds to the last PLP group (S510600).

Based upon the determined result, when it is determined that theselected PLP group does not correspond to the last PLP group, thereceiver may return to the process step S510300, so as to select thenext PLP group. Alternatively, when it is determined that the selectedPLP group corresponds to the last PLP group, the receiver may determinewhether or not the current channel corresponds to the last channel(S510600).

Then, based upon the determined result, when it is determined that thecurrent channel does not correspond to the last channel, the receivermay return to the process step S510100, so as to tune to the nextchannel. And, alternatively, when it is determined that the currentchannel corresponds to the last channel, the receiver may use the storedservice information so as to tune to a first service or a pre-setservice (S510700).

FIG. 43 to FIG. 47 will hereinafter describe the third embodiment of thepresent invention.

FIG. 43 illustrates a conceptual view of a correlation between a serviceaccording to the third embodiment of the present invention and a PLPgroup.

When a channel is scanned by the receiver according to the secondembodiment of the present invention, the receiver may not be capable ofscanning (or searching through) the entire PLP, which transmits thecomponents included in a single service. Since the components includedin each of the multiple services are transmitted through each PLP, a PLPthat does not include PSI/SI may also exist.

Therefore, in the third embodiment of the present invention, PSI/SI,such as the PAT/PMT, may be transmitted to a random PLP included in themultiple PLP regions, so that the entire PLP transmitting the componentsincluded in a single service can be scanned (or searched). As describedabove, in the description of the present invention, the PLP transmittingservice configuration information, such as the PAT/PMT, may also bereferred to as a base PLP. More specifically, when the receiver decodesthe base PLP, information on the remaining component PLPs included in asingle service may be acquired. Eventually, according to the thirdembodiment of the present invention, instead of acquiring signalinginformation by processing the entire transport stream, by processing thesignaling information included in a physical layer, so as to acquiresignaling information included in the base PLP, the receiver may acquiresignaling information respective to the transport stream.

As shown in FIG. 43, the L1 signaling information region 511100according to the third embodiment of the present invention may includeinformation respective to each of the multiple PLPs, i.e., aPLP_GROUP_ID field, a PLP_ID field, a PLP_COMPONENT_TYPE field, and soon. Additionally, the L2 signaling information region 511200 may includean NIT and an SDT. Herein, the NIT may include a BASE_PLP_ID field,which is matched with the PLP_ID field being included in the L1signaling information region 511100. And, by using the BASE_PLP_IDfield, the receiver may identify a base PLP, which transmits thePMT/PAT. Furthermore, the SDT may include a transport_stream_id field,which is identical to the transport_stream_id included in the NIT, and aservice_id field. And, by using the SDT, the receiver may differentiateeach of the services being transmitted through a specific transportstream.

Additionally, since the PMT being transmitted through the base PLPinclude a program_number field, which is matched with the service_idfield included in the SDT, by using the program_number field, thereceiver may verify the program number included in the selected service.Also, by referring to the stream type field included in the PMT, thereceiver may recognize the type of the current stream, and by using thePLP_ID field of the component_id_descriptor included in the PMT, thereceiver may determine the correlation between the PLP and thecomponent, thereby being capable of receiving/processing the PLPbest-fitting the PLP.

Moreover, by using the PLP_PROFILE field included in the PMT, thereceiver may receive a PLP transmitting a specifically distinguishedservice component, such as a mobile service, high picture qualityservice, and so on, in accordance with the receiver characteristic.Thus, a transport stream corresponding to the receiver characteristicmay be recovered.

Eventually, the receiver may identify and select the base PLP of eachtransport stream by using the BASE_PLP_ID field, which is included inthe NIT, and the receiver may receive a PMT, which is transmittedthrough the base PLP. Additionally, the receiver may identify and selecta wanted (or desired) service by using the service_id field, which isincluded in the SDT. Moreover, in addition to being capable of selectingall of the PLPs that are included in a component, which is included in asingle service, by using the PLP_PROFILE field, the receiver may receivea PLP in accordance with the receiver characteristic.

Hereinafter, the L1 signaling information region L1 511100, the NIT, theSDT, and the PMT according to the third embodiment of the presentinvention will be described in detail.

Since the L1 signaling information region 511100 according to the thirdembodiment of the present invention is identical to the L1 signalinginformation region 503200 shown in FIG. 36, a detailed description ofthe same will be omitted for simplicity.

The PLP_PROFILE field may identify whether the corresponding PLP is amandatory (or required) PLP or an optional (or selective) PLP. Forexample, in case the component being transmitted through the PLP isidentified (or distinguished) as a base layer or an enhancement layer,the PLP transmitting the base layer becomes the mandatory PLP, and thePLP transmitting the enhancement layer becomes the optional PLP. Morespecifically, depending upon the receiver characteristic, such as amobile receiver, an HD receiver, and so on, the receiver may use thePLP_PROFILE field so as to verify by which receiver the component of thebroadcast service being transmitted to the current PLP may be used, anddepending upon the receiver characteristic, the receiver may determinewhether or not to receive the current PLP.

The NIT according to the third embodiment of the present invention issimilar to the NIT according to the second embodiment of the presentinvention, which is described above with reference to FIG. 40. However,unlike the NIT according to the second embodiment of the presentinvention, the NIT according to the third embodiment of the presentinvention may further include a BASE_PLP_ID field.

Herein, the BASE_PLP_ID field is used for identifying the base PLP. And,the base PLP may transmit PSI/SI information of a correspondingtransport stream, such as the PMT/PAT. Additionally, the BASE_PLP_IDfield may be included in a delivery_system_descriptor loop of the NIT.

The PMT according to the third embodiment of the present invention mayinclude a program number field and a PID loop. And, the PID loop mayinclude a component_id_descriptor field. Herein, thecomponent_id_descriptor field may include a PLP_PROFILE field and aPLP_ID field.

The contents of the program_number field and the PLP_ID field areidentical to those described above with reference to FIG. 35 and FIG.40. And, since the PLP_PROFILE field is identical to the PLP_PROFILEfield included in the L1 signaling information region 511100, a detaileddescription of the same will be omitted for simplicity.

FIG. 44 illustrates an exemplary delivery system descriptor fieldaccording to the third embodiment of the present invention.

As shown in FIG. 44, the delivery_system_descriptor field according tothe third embodiment of the present invention is identical to thedelivery_system_descriptor field according to the first embodiment ofthe present invention, which is shown in FIG. 38. However, unlike thedelivery_system_descriptor field according to the first embodiment ofthe present invention, the delivery_system_descriptor field according tothe third embodiment of the present invention may further include aBASE_PLP_ID field. Since the description of the BASE_PLP_ID field isidentical to that of FIG. 43, a detailed description of the same will beomitted for simplicity.

FIG. 45 illustrates an exemplary component ID descriptor field accordingto the third embodiment of the present invention.

As shown in FIG. 45, the component_id_descriptor field, which isincluded in the PID loop of the PMT according to the third embodiment ofthe present, is identical to the component_id_descriptor field accordingto the second embodiment of the present invention, which is shown inFIG. 40. However, the component_id_descriptor field according to thethird embodiment of the present invention may include a PLP_PROFILEfield instead of the PLP_COMPONENT_TYPE field. Herein, since thedescription of the PLP_PROFILE field is identical to that of FIG. 43, adetailed description of the same will be omitted for simplicity.

FIG. 46 illustrates an exemplary PLP_PROFILE field according to thethird embodiment of the present invention.

As shown in FIG. 46, the PLP_PROFILE field may provide information in abit-unit selector format.

The PLP_PROFILE field may indicate information on a video component inaccordance with the field value. For example, when the field value isequal to 0x00, this signifies a common profile and indicates that thevideo component corresponds to a component that can be received and usedby any receiver. When the field value is equal to 0x01, this indicatesthat the video component corresponds to a component that can be usedonly by mobile receivers, and when the field value is equal to 0x02,this indicates that the video component corresponds to an HD profilecomponent that can be used only by HD receivers. And, when the fieldvalue is equal to 0x03, this indicates that the component can be appliedto both mobile receivers and HD receivers.

FIG. 47 illustrates a flow chart showing the process steps of a servicescanning method of the receiver according to the third embodiment of thepresent invention.

After receiving a TP type broadcast signal, the receiver may tune to anext channel (S515100). In this case, in order to receive a servicewanted (or desired) by the user, the receiver requires information onthe service included in the transmission frame, which is beingtransmitted through the respective channel. Although this process stepis not shown in the drawing, this process step may be performed by thetuner of the receiver and may be modified or varied in accordance withthe intentions of the system designer.

Then, the receiver may decode the L1 signaling information region 511100included in the transmission frame, so as to acquire a PLP ID, a PLPGroup ID, and a system ID, which are included in the transmission frame(S515150). This process step may be performed by the BICM decoder 107300of the broadcast signal receiver according to the present invention.And, more specifically, this process step may be performed by a seconddecoding block 110200. Respectively, the BICM encoder 101300 of thebroadcast signal transmitter according to the present invention mayencode the signaling information, so as to generate and transmit L1signaling information. This is a detail that can be varied or modifiedby the intentions of the system designer.

Thereafter, the receiver may identify the PLP groups by using thedecoded PLP Group ID, so as to select the desired PLP group, and maydecode the PLP including the L2 signaling information region 511200.This process step may be performed by the BICM decoder 107300 of thebroadcast signal receiver according to the present invention. And, morespecifically, this process step may be performed by a first decodingblock 110100. Respectively, the BICM encoder 101300 of the broadcastsignal transmitter according to the present invention may encode thesignaling information, so as to generate and transmit L1 signalinginformation. This is a detail that can be varied or modified by theintentions of the system designer.

Additionally, the receiver may decode the NIT included in the L2signaling information region 511200 and may use the BASE PLP_ID field,which is included in the NIT, so as to locate (or find) the base PLP ofeach TS (S515250). This process step may be performed by the BICMdecoder 107300 of the broadcast signal receiver according to the presentinvention. And, more specifically, this process step may be performed bya first decoding block 110100. Respectively, the BICM encoder 101300 ofthe broadcast signal transmitter according to the present invention mayencode the signaling information, so as to generate and transmit L1signaling information. This is a detail that can be varied or modifiedby the intentions of the system designer.

Subsequently, the receiver may use the transport_stream_id field, whichis included in the NIT, so as to identify the transport stream includedin the base PLP (S515300). This process step may be performed by theBICM decoder 107300 of the broadcast signal receiver according to thepresent invention. And, more specifically, this process step may beperformed by a first decoding block 110100. Respectively, the BICMencoder 101300 of the broadcast signal transmitter according to thepresent invention may encode the signaling information, so as togenerate and transmit L1 signaling information. This is a detail thatcan be varied or modified by the intentions of the system designer.

The receiver may use the PLP_PROFILE field, which is included in acomponent ID descriptor field of the decoded PMT, so as to verify whichreceiver may use the component of the broadcast service, which is beingtransmitted to the current PLP in accordance with the receivercharacteristic, such as mobile receiver, HD receiver, and so on.Accordingly, by using the PLP_ID field, the receiver may selectivelyreceive the PLP that is requested to be received.

Thereafter, the receiver may store the information related to thecorrelation between the component and the PLP, based upon the receivercharacteristic (S515350). The information related to the correlationbetween the component and the PLP may include a correlation (orconnection) between the PID information of the PMT and the PLP id field,which is included in the component ID descriptor field.

Subsequently, the receiver may determine whether or not the current TScorresponds to the last TS within the PLP group (S515400).

When it is determined that the current TS does not correspond to thelast TS, the receiver may return to the process step S515250, so as toparse the NIT and to acquire the base PLP of each TS by using theBASE_PLP_ID field. Alternatively, when it is determined that the currentTS corresponds to the last TS, the receiver may determine whether or notthe current PLP group corresponds to the last PLP group (S515450).

When it is determined that the selected PLP group does not correspond tothe last PLP group, the receiver may return to the process step S515200,so as to select the next PLP group and to decode a common PLP.Alternatively, when it is determined that the selected PLP groupcorresponds to the last PLP group, the receiver may determine whether ornot the current channel corresponds to the last channel (S515500).

Thereafter, when it is determined that the current channel does notcorrespond to the last channel, the receiver may return to the processstep S515100, so as to tune to the next channel. And, alternatively,when it is determined that the current channel corresponds to the lastchannel, the receiver may tune to a first service or a pre-set service(S515550).

FIG. 48 to FIG. 50 will hereinafter describe the fourth embodiment ofthe present invention.

FIG. 48 illustrates a conceptual view of a correlation between a serviceaccording to the fourth embodiment of the present invention and a PLPgroup.

In case of transmitting a broadcast signal of a IP format, the fourthembodiment of the present invention corresponds to a signaling methodfor recovering a transport stream by acquiring a service IP address andinformation on a component type and information on a component address,which are included in a PLP, and by merging multiple PLPs being includedin the same PLP group.

As shown in FIG. 48, the L1 signaling information region 516100according to the fourth embodiment of the present invention may includeinformation related to each of the multiple PLPs, i.e., a PLP_GROUP_IDfield, a PLP_ID field, and so on. Also, the L2 signaling informationregion 516200 may include an IP information table, and the IPinformation table may include a IP_address_list( ) field and adescriptor. The IP_address_list( ) field may include IP addressinformation for receiving a Bootstrap, and the descriptor may includethe same PLP_GROUP_ID field and PLP_ID field that are included in the L1signaling information region 516100. Since the IP_address_list( ) fieldand the descriptor form a pair, by using this pair, the receiver may becapable of knowing which PLP group is correlated to a specific IPstream. Thereafter, the receiver may use the IP_address_list( ) field,so as to receive a Bootstrap. Herein, the bootstrap includes aboot_IP_address field. And, by using the boot_IP_address field, thereceiver may acquire an IP address that can receiver (or acquire) aservice guide information or broadcast content guide information.

Subsequently, by using the received bootstrap, the receiver may receiverservice guide information, such as ESG (Electronic Service Guide)/BCG(Broadcast Contents Guide). The service guide information or broadcastcontents guide information may be transmitted through an interactivechannel and may be received through an IP stream, which is included in aspecific PLP. This may vary depending upon the intentions of the systemdesigner. The receiver may use the service_id field, the component_typefield, and the component_IP_address field, which are included in theESG/BCG, so as to receive a desired (or wanted) service and servicecomponents.

Eventually, by using the component_IP_address included in the ESG/BCG,or by using the boot_IP_address field of the bootstrap, the receiver mayacquire an IP address for each service and service components. And, byusing the IP_address_list( ) field and the PLP_GROUP_ID field of the IPinformation table, the receiver may be capable of knowing which IPstream/packet is correlated to the PLP group. Thereafter, the receivermay merge the service components that are included in a PLP having thesame PLP_GROUP_ID field included in the L1 signaling information region516100, so as to recover a service.

Hereinafter, the L1 signaling information, the IP information table, abootstrap, and an ESG/BCG will be described in detail.

The L1 signaling information region 503200 according to the fourthembodiment of the present invention may include the same fields includedin the L1 signaling information region 503200, which is described inFIG. 35. And, the receiver may use the PLP_COMPONENT_TYPE field so as todetermine whether or not the L1 signaling information region 503200 ismatched with the component_type field included in the ESG/BCG.

The IP information table according to the fourth embodiment of thepresent invention corresponds to a table include IP-related information,i.e., information on an IP address and so on. Herein, the receiver maybe capable of knowing how the IP is being transmitted from the IPinformation table through the transport stream.

The IP information data may include an IP_addr_location loop, and theIP_addr_location loop may include a target_IP_add_descriptor field andan IP/MAC_location_information field.

The target_IP_add_descriptor( ) field may include an IP_address_list( )field, and the IP_address_list( ) field may include information relatedto the IP address. According to the embodiment of the present invention,the present invention includes an IP address/port field. Depending uponthe number of ports, a plurality of the IP address/port fields may beincluded. The IP/MAC_location_information field may also be referred toas an IP/MAC_location description field, which may be used forconnecting the PLP_COMPONENT_TYPE field included in the L1 signalinginformation field 516100 to the IP. The IP/MAC_location_informationfield may include the same PLP_ID field and PLP_GROUP_ID field as thePLP_ID field and the PLP_GROUP_ID field, which are included in the L1signaling information field.

Hereinafter, each field included in the bootstrap and ESG/BCG shown inFIG. 48 will be described in detail.

Herein, the Bootstrap may include a boot_IP_addr field, and theboot_IP_addr field may identify a booting address of the IP.

The ESG/BCG may include a NUM_SERVICE loop. Herein, the NUM_SERVICE loopmay include a respective service_name field, service_id field, and aNUM_COMPONENT loop for each of the multiple services.

The service_name field may be used for indicating the name of eachservice, and the service_id field may be used for identifying eachservice.

The NUM_COMPONENT loop corresponds to a loop include information on themultiple components, which are included in a service. Herein, theNUM_COMPONENT loop may include a component_type field and acomponent_IP_address field.

The component_type field may be used for identifying component types ofthe service. And, examples of the components according to the presentinvention may include video components, video extension components,audio components, data components, and so on. Also, the component_typefield may be matched with the PLP_COMPONENT_TYPE field, which isincluded in the L1 signaling information region 516100.

The component IP address field may identify the IP address of eachcomponent.

FIG. 49 illustrates an exemplary IP/MAC_loc_information field accordingto the fourth embodiment of the present invention.

As shown in FIG. 49, the IP/MAC_loc_information field according to thefourth embodiment of the present invention may include the same fieldsas the component id descriptor field according to the second embodimentof the present invention, which is described above with reference toFIG. 41. Herein, however, the IP/MAC_loc_information field according tothe fourth embodiment of the present invention may include aPLP_GROUP_ID field instead of the PLP_COMPONENT_TYPE field. Since thedescription of each field is identical to that of FIG. 35 and FIG. 41,detailed description of the same will be omitted for simplicity.

FIG. 50 illustrates a flow chart showing the process steps of a servicescanning method of the receiver according to the fourth embodiment ofthe present invention.

After receiving an IP type broadcast signal, the receiver may tune to anext channel (S518100). In this case, in order to receive a servicedesired by the user, the receiver requires information on the serviceincluded in the transmission frame, which is being transmitted throughthe respective channel. Although this process step is not shown in thedrawing, this process step may be performed by the tuner of the receiverand may be modified or varied in accordance with the intentions of thesystem designer.

Then, the receiver may decode the L1 signaling information region 516100included in the transmission frame, so as to acquire a PLP_ID and a PLPGroup ID, which are included in the transmission frame (S518200). Thisprocess step may be performed by the BICM decoder 107300 of thebroadcast signal receiver according to the present invention.Respectively, the BICM encoder 101300 of the broadcast signaltransmitter according to the present invention may encode the signalinginformation, so as to generate and transmit L1 signaling information.This is a detail that can be varied or modified by the intentions of thesystem designer.

Thereafter, the receiver may identify the PLP groups by using thedecoded PLP group ID so as to select a desired PLP group, and thereceiver may then decode the L2 signaling information region 516200 andthe PLP including the PSI/SI and metadata (5518300). This process stepmay be performed by the BICM decoder 107300 of the broadcast signalreceiver according to the present invention.

The receiver may decode the IP information table included in the decodedL2 signaling information region 516200, and the receiver may also decodethe metadata included in the PLP (S518400). Additionally, the receivermay acquire service information associated with information on thetransmitting system and PLP structures, thereby being capable of storingthe acquired service information (S518400). The service informationaccording to the present invention may include a service IP address, acomponent IP address, and so on. This process step may be performed bythe BICM decoder 107300 of the broadcast signal receiver according tothe present invention.

Subsequently, the receiver may determine whether or not the currentlyselected PLP group corresponds to the last PLP group (S518500).

Based upon the determined result, when it is determined that theselected PLP group does not correspond to the last PLP group, thereceiver may return to the process step S518300, so as to select thenext PLP group. Alternatively, when it is determined that the selectedPLP group corresponds to the last PLP group, the receiver may determinewhether or not the current channel corresponds to the last channel(S518600).

Then, based upon the determined result, when it is determined that thecurrent channel does not correspond to the last channel, the receivermay return to the process step S518100, so as to tune to the nextchannel. And, alternatively, when it is determined that the currentchannel corresponds to the last channel, the receiver may use the storedservice information so as to tune to a first service or a pre-setservice (S518700).

FIG. 51 illustrates a flow chart showing the process steps of abroadcast signal receiving method according to an embodiment of thepresent invention.

An OFDM demodulator 107100 of the receiver according to the embodimentof the present invention may receive multiple broadcast signalsincluding a transmission frame for transmitting broadcast services andmay then perform OFDM demodulation on the received broadcast signals(S5000). In this case, the transmission frame may include a preamble andmultiple PLPs including a base layer and an enhancement layer of abroadcast service. Additionally, the preamble may include firstsignaling information, and the multiple PLPs may include secondsignaling information and third signaling information. As describedabove, in the description of the present invention, the P1 signalinginformation region 503100, the L1 signaling information region 503200,and the common PLP region 503300 may be collectively referred to as apreamble. Furthermore, only the P1 signaling information region 503100and the L1 signaling information region 503200 may be collectivelyreferred to as the preamble. This may be varied depending upon theintentions of the system designer.

The first signaling information may include L1 signaling information,and the first signaling information may be located after a P1 symbol ofthe transmission frame. The second signaling information may include L2signaling information. And, according to the embodiment of the presentinvention, the second signaling information may include the NIT shown inFIG. 43.

Among the multiple PLPs, the common PLP may include the second signalinginformation, and the common PLP may be located after the first signalinginformation of the transmission frame. Moreover, as described above,depending upon the intentions of the system designer, the common PLP mayalso be included in the preamble.

Furthermore, among the multiple PLPs, one PLP may include thirdsignaling information, and such PLP may be referred to as a base PLP.The second signaling information may include NIT, SDT, and so on, andthe third signaling information may include PMT/PAT, and so on.

The first signaling information may include an identifier, e.g., thePLP_ID field shown in FIG. 43, for identifying each of the multiplePLPs. And, the second signaling information may include a descriptor,e.g., the delivery_system_descriptor shown in FIG. 43, which includes anidentifier, e.g., the BASE_PLP_ID field shown in FIG. 43, for indicatinga PLP including the third signaling information. Herein, the thirdsignaling information may include an identifier, e.g., the PLP_PROFILEfield shown in FIG. 43, for identifying which type of data, among thebase layer and the enhancement layer of a broadcast service, areincluded in each of the multiple PLPs.

Afterwards, a MISO decoder 108170 of the broadcast signal receiveraccording to the embodiment of the present invention may decode each ofthe OFDM-demodulated broadcast signals by using any one of the MIMO,MISO, and SISO methods, and may then output the transmission frame(S5010).

Subsequently, a second decoding block 110200, which is included in theBICM decoder 107300 of the broadcast signal receiver according to theembodiment of the present invention, may decoder the first signalinginformation, which is included in the preamble of the outputtedtransmission frame (S5020).

Thereafter, a first BICM decoding block 110100, which is included in theBICM decoder 107300 of the broadcast signal receiver according to theembodiment of the present invention, may decode the second signalinginformation (S5030). And, the first BICM decoding block 110100 may usethe decoded second signaling information so as to decode the PLPincluding the third signaling information (S5040). Then, the first BICMdecoding block 110100 may use the third signaling information so as toselectively decode the plurality of PLPs (S5050). More specifically, inthe method of selectively decoding the plurality of PLPs by using thethird signaling information, a specific PLP may be selectively decodedby using an identifier for identifying each of the multiple PLPs and byusing an identifier for identifying which type of data, among the baselayer and the enhancement layer of a broadcast service, are included ineach of the multiple PLPs.

MODE FOR CARRYING OUT THE PRESENT INVENTION

As described above, the present invention is described with respect tothe best mode for carrying out the present invention.

INDUSTRIAL APPLICABILITY

As described above, the present invention may be fully (or entirely) orpartially applied to digital broadcasting systems.

1-4. (canceled)
 5. A method for transmitting broadcast signals, whereinthe method comprising: input processing input streams to generate dataof PLP (Physical Layer Pipe) carrying at least one service or at leastone service component; BCH (Bose Chaudhuri Hocquenghem) encoding on databy a BCH scheme; LDCP (Low Density Parity Check) encoding on the BCHencoded data by an LDPC scheme; mapping the LDPC encoded data ontoconstellations; MIMO (Multiple-Input Multiple-Output) processing themapped data; time interleaving the MIMO processed data; building atleast one signal frame, wherein each signal frame comprises a preambleincluding basic transmission parameters and signaling information fordecoding data symbols and the data symbols including the timeinterleaved data; modulating data in the built at least one signal frameby using an OFDM (Orthogonal Frequency Divisional Multiplexing Scheme);and transmitting the broadcast signals including the modulated data. 6.The method of claim 5, wherein the at least one service componentincludes at least one service component for a base layer and anenhancement layer for a scalable video coding service.
 7. The method ofclaim 5, wherein a specific PLP carries information for describing aservice.
 8. The method of claim 7, wherein the preamble includesidentification information for identifying the specific PLP.
 9. Themethod of claim 5, wherein the method further includes; frequencyinterleaving the built at least one signal frame.
 10. An apparatus fortransmitting broadcast signals, wherein the apparatus comprising: aninput processor configured to input process input streams to generatedata of PLP (Physical Layer Pipe) carrying at least one service or atleast one service component; a BCH (Bose Chaudhuri Hocquenghem) encoderconfigured to encode on data by a BCH scheme; an LDCP (Low DensityParity Check) encoder configured to encode on the BCH encoded data by anLDPC scheme; a mapper configured to map the LDPC encoded data ontoconstellations; a MIMO (Multiple-Input Multiple-Output) processorconfigured to process the mapped data; a time interleaver configured totime interleave the MIMO processed data; a frame builder configure tobuild at least one signal frame, wherein each signal frame comprises apreamble including basic transmission parameters and signalinginformation for decoding data symbols and the data symbols including thetime interleaved data; a modulator configured to modulate data in thebuilt at least one signal frame by using an OFDM (Orthogonal FrequencyDivisional Multiplexing Scheme); and a transmission unit configured totransmit the broadcast signals including the modulated data.
 11. Theapparatus of claim 10, wherein the at least one service componentincludes at least one service component for a base layer and anenhancement layer for a scalable video coding service.
 12. The apparatusof claim 10, wherein a specific PLP carries information for describing aservice.
 13. The apparatus of claim 12, wherein the preamble includesidentification information for identifying the specific PLP.
 14. Theapparatus of claim 10, wherein the apparatus further includes; afrequency interleaver configured to frequency interleave the built atleast one signal frame.
 15. A method for receiving broadcast signals,wherein the method comprising: receiving the broadcast signals;demodulating the received broadcast signals by using an OFDM (OrthogonalFrequency Divisional Multiplexing Scheme); parsing at least one signalframe from the demodulated broadcast signals, wherein each signal framecomprises a preamble including basic transmission parameters andsignaling information for decoding data symbols and data symbolsincluding data of PLP (Physical Layer Pipe) carrying at least oneservice or at least one service component; time de-interleaving the datain the data symbols; MIMO (Multiple-Input Multiple-Output) processingthe time de-interleaved data; de-mapping the MIMO processed data; LDCP(Low Density Parity Check) decoding on the de-mapped data by an LDPCscheme; BCH (Bose Chaudhuri Hocquenghem) decoding on the LDPC decodeddata by a BCH scheme; and output processing BCH decoded data.
 16. Themethod of claim 15, wherein the at least one service component includesat least one service component for a base layer and an enhancement layerfor a scalable video coding service.
 17. The method of claim 15, whereina specific PLP carries information for describing a service.
 18. Themethod of claim 17, wherein the preamble includes identificationinformation for identifying the specific PLP.
 19. The method of claim15, wherein the method further includes; frequency de-interleaving thedemodulated broadcast signals.
 20. An apparatus for receiving broadcastsignals, wherein the apparatus comprising: a receiving unit configuredto receive the broadcast signals; a demodulator configured to demodulatethe received broadcast signals by using an OFDM (Orthogonal FrequencyDivisional Multiplexing Scheme); a frame parser configured to parse atleast one signal frame from the demodulated broadcast signals, whereineach signal frame comprises a preamble including basic transmissionparameters and signaling information for decoding data symbols and datasymbols including data of PLP (Physical Layer Pipe) carrying at leastone service or at least one service component; a time de-interleaverconfigured to time de-interleave the data in the data symbols; a MIMO(Multiple-Input Multiple-Output) processor configured to process thetime de-interleaved data; a de-mapper configured to de-map the MIMOprocessed data; an LDCP (Low Density Parity Check) decoder configured todecode on the de-mapped data by an LDPC scheme; a BCH (Bose ChaudhuriHocquenghem) decoder configured to decode on the LDPC decoded data by aBCH scheme; and an output processor configured to output process BCHdecoded data.
 21. The apparatus of claim 20, wherein the at least oneservice component includes at least one service component for a baselayer and an enhancement layer for a scalable video coding service. 22.The apparatus of claim 20, wherein a specific PLP carries informationfor describing a service.
 23. The apparatus of claim 22, wherein thepreamble includes identification information for identifying thespecific PLP.
 24. The apparatus of claim 20, wherein the apparatusfurther includes; a frequency de-interleaver configured to frequencyde-interleave the demodulated broadcast signals.